diff --git a/Cargo.lock b/Cargo.lock
index dbcbedf81..85cd3764a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6968,6 +6968,7 @@ dependencies = [
  "tokenizers",
  "tokio",
  "tokio-util 0.7.16",
+ "toml 0.8.23",
  "tracing",
  "wandb",
 ]
@@ -6982,6 +6983,7 @@ dependencies = [
  "cfg_eval",
  "psyche-core",
  "serde",
+ "serde_json",
  "serde_with",
  "ts-rs",
 ]
@@ -7073,6 +7075,7 @@ dependencies = [
 name = "psyche-deserialize-zerocopy-wasm"
 version = "0.2.0"
 dependencies = [
+ "psyche-coordinator",
  "psyche-core",
  "psyche-solana-coordinator",
  "serde",
@@ -8106,6 +8109,7 @@ dependencies = [
  "clap-markdown",
  "psyche-coordinator",
  "psyche-core",
+ "psyche-data-provider",
  "psyche-solana-authorizer",
  "psyche-solana-coordinator",
  "psyche-solana-rpc",
diff --git a/architectures/centralized/client/src/app.rs b/architectures/centralized/client/src/app.rs
index 8f6a9bcca..aab6e66b9 100644
--- a/architectures/centralized/client/src/app.rs
+++ b/architectures/centralized/client/src/app.rs
@@ -5,7 +5,8 @@ use psyche_centralized_shared::{ClientId, ClientToServerMessage, ServerToClientM
 use psyche_client::HubUploadInfo;
 use psyche_client::UploadInfo;
 use psyche_client::{
-    Client, ClientTUI, ClientTUIState, NC, RunInitConfig, TrainArgs, read_identity_secret_key,
+    Client, ClientTUI, ClientTUIState, ModelExtraData, NC, RunInitConfig, TrainArgs,
+    read_identity_secret_key,
 };
 use psyche_coordinator::{Coordinator, HealthChecks, model};
 use psyche_metrics::ClientMetrics;
@@ -110,6 +111,7 @@ pub async fn build_app(
     let hub_read_token = std::env::var("HF_TOKEN").ok();
     let eval_tasks = p.eval_tasks()?;
     let checkpoint_config = p.checkpoint_config()?;
+    let model_extra_data_override: Option<ModelExtraData> = p.model_extra_data_override()?;
     let wandb_info = p.wandb_info(format!(
         "{}-{}",
         p.run_id.clone(),
@@ -153,6 +155,7 @@ pub async fn build_app(
         max_concurrent_parameter_requests: p.max_concurrent_parameter_requests,
         device: p.device,
         sidecar_port: p.sidecar_port,
+        model_extra_data_override,
     };
     let app = App {
         cancel,
diff --git a/architectures/centralized/server/src/app.rs b/architectures/centralized/server/src/app.rs
index 402146817..f2a4c7797 100644
--- a/architectures/centralized/server/src/app.rs
+++ b/architectures/centralized/server/src/app.rs
@@ -1,7 +1,7 @@
-use anyhow::{Result, anyhow, bail};
+use anyhow::{Result, bail};
 use async_trait::async_trait;
 use psyche_centralized_shared::{ClientId, ClientToServerMessage, ServerToClientMessage};
-use psyche_coordinator::model::{self, Checkpoint, LLM, LLMTrainingDataLocation, Model};
+use psyche_coordinator::model::{self, Checkpoint, Model};
 use psyche_coordinator::{
     Client, ClientState, Coordinator, CoordinatorError, HealthChecks, Round, RunState,
     SOLANA_MAX_NUM_CLIENTS, TickResult,
@@ -148,12 +148,18 @@ impl App {
     }
 }
 
+fn default_data_server_port() -> u16 {
+    9088
+}
+
 #[derive(Serialize, Deserialize, Debug)]
 pub struct DataServerInfo {
     pub dir: PathBuf,
     pub token_size: TokenSize,
     pub seq_len: usize,
     pub shuffle_seed: [u8; 32],
+    #[serde(default = "default_data_server_port")]
+    pub port: u16,
 }
 
 impl App {
@@ -176,72 +182,58 @@ impl App {
 
             debug!("potentially launching data server...");
 
-            let training_data_server = match &coordinator.model {
-                Model::LLM(LLM {
-                    data_location,
-                    checkpoint,
-                    ..
-                }) => {
-                    if let LLMTrainingDataLocation::Server(url) = data_location {
-                        match checkpoint {
-                            Checkpoint::Hub(hub_repo) => {
-                                let repo_id = String::from(&hub_repo.repo_id);
-                                let revision = hub_repo.revision.map(|bytes| (&bytes).into());
-                                if revision.is_some()
-                                    || !tokio::fs::try_exists(PathBuf::from(repo_id.clone()))
-                                        .await
-                                        .unwrap_or_default()
-                                {
-                                    download_model_repo_async(&repo_id, revision, None, None, None, true)
-                                        .await?;
-                                }
-                            }
-                            Checkpoint::Ephemeral => {
-                                bail!("Can't start up a run with an Ephemeral checkpoint.")
-                            }
-                            Checkpoint::Dummy(_) => {
-                                // ok!
-                            }
-                            Checkpoint::P2P(_) | Checkpoint::P2PGcs(_) => {
-                                bail!("Can't start up a run with a P2P checkpoint.")
-                            }
-                            Checkpoint::Gcs(gcs_repo) => {
-                                let bucket: String = (&gcs_repo.bucket).into();
-                                let prefix: Option<String> =
-                                    gcs_repo.prefix.map(|p| (&p).into());
-                                download_model_from_gcs_async(&bucket, prefix.as_deref()).await?;
-                            }
-                        }
-
-                        let server_addr: SocketAddr = String::from(url).parse().map_err(|e| {
-                            anyhow!("Failed to parse training data server URL {:?}: {}", url, e)
-                        })?;
-                        let data_server_port = server_addr.port();
-                        let DataServerInfo {
-                            dir,
-                            seq_len,
-                            shuffle_seed,
-                            token_size
-                        } = data_server_config.ok_or_else(|| anyhow!(
-                            "Coordinator state requires we host training data, but no --data-config passed."
-                        ))?;
-
-                        let local_data_provider = LocalDataProvider::new_from_directory(
-                            dir,
-                            token_size,
-                            seq_len,
-                            Shuffle::Seeded(shuffle_seed),
-                        )?;
-
-                        let (tx, backend) = ChannelCoordinatorBackend::new();
-                        let data_server =
-                            DataProviderTcpServer::start(local_data_provider, backend, data_server_port)
+            let training_data_server = if let Some(DataServerInfo {
+                dir,
+                seq_len,
+                shuffle_seed,
+                token_size,
+                port,
+            }) = data_server_config
+            {
+                // Download model if needed based on checkpoint type
+                let Model::LLM(llm) = &coordinator.model;
+                match &llm.checkpoint {
+                    Checkpoint::Hub(hub_repo) => {
+                        let repo_id = String::from(&hub_repo.repo_id);
+                        let revision = hub_repo.revision.map(|bytes| (&bytes).into());
+                        if revision.is_some()
+                            || !tokio::fs::try_exists(PathBuf::from(repo_id.clone()))
+                                .await
+                                .unwrap_or_default()
+                        {
+                            download_model_repo_async(&repo_id, revision, None, None, None, true)
                                 .await?;
-                        Some((tx, data_server))
-                    } else {
-                        None
+                        }
+                    }
+                    Checkpoint::Ephemeral => {
+                        bail!("Can't start up a run with an Ephemeral checkpoint.")
+                    }
+                    Checkpoint::Dummy(_) => {
+                        // ok!
+                    }
+                    Checkpoint::P2P(_) | Checkpoint::P2PDummy | Checkpoint::P2PGcs(_) => {
+                        bail!("Can't start up a run with a P2P checkpoint.")
+                    }
+                    Checkpoint::Gcs(gcs_repo) => {
+                        let bucket: String = (&gcs_repo.bucket).into();
+                        let prefix: Option<String> = gcs_repo.prefix.map(|p| (&p).into());
+                        download_model_from_gcs_async(&bucket, prefix.as_deref()).await?;
                     }
                 }
+
+                let local_data_provider = LocalDataProvider::new_from_directory(
+                    dir,
+                    token_size,
+                    seq_len,
+                    Shuffle::Seeded(shuffle_seed),
+                )?;
+
+                let (tx, backend) = ChannelCoordinatorBackend::new();
+                let data_server =
+                    DataProviderTcpServer::start(local_data_provider, backend, port).await?;
+                Some((tx, data_server))
+            } else {
+                None
             };
             debug!("data server work done.");
 
@@ -253,8 +245,7 @@ impl App {
             } else {
                 (None, None)
             };
-            let (cancel, tx_tui_state) =
-                maybe_start_render_loop(tabs)?;
+            let (cancel, tx_tui_state) = maybe_start_render_loop(tabs)?;
 
             let mut tick_interval = interval(Duration::from_millis(500));
             tick_interval.set_missed_tick_behavior(MissedTickBehavior::Skip); //important!
@@ -293,7 +284,9 @@ impl App {
                 withdraw_on_disconnect,
                 pause,
             })
-        }.instrument(info_span!("App::new")).await
+        }
+        .instrument(info_span!("App::new"))
+        .await
     }
 
     pub async fn run(&mut self) -> Result<()> {
diff --git a/architectures/centralized/testing/tests/integration_tests.rs b/architectures/centralized/testing/tests/integration_tests.rs
index 81943e827..656e6951a 100644
--- a/architectures/centralized/testing/tests/integration_tests.rs
+++ b/architectures/centralized/testing/tests/integration_tests.rs
@@ -9,10 +9,7 @@ use psyche_centralized_testing::{
         spawn_clients_with_training_delay,
     },
 };
-use psyche_coordinator::{
-    RunState,
-    model::{Checkpoint, HubRepo},
-};
+use psyche_coordinator::{RunState, model::Checkpoint};
 use tracing::info;
 
 #[test_log::test(tokio::test(flavor = "multi_thread"))]
@@ -639,7 +636,7 @@ async fn client_join_in_training_and_get_model_using_p2p() {
 
     assert_with_retries(
         || server_handle.get_checkpoint(),
-        std::mem::discriminant(&Checkpoint::P2P(HubRepo::dummy())),
+        std::mem::discriminant(&Checkpoint::P2PDummy),
     )
     .await;
 
@@ -722,7 +719,7 @@ async fn two_clients_join_in_training_and_get_model_using_p2p() {
 
     assert_with_retries(
         || server_handle.get_checkpoint(),
-        std::mem::discriminant(&Checkpoint::P2P(HubRepo::dummy())),
+        std::mem::discriminant(&Checkpoint::P2PDummy),
     )
     .await;
 
diff --git a/architectures/decentralized/solana-client/src/app.rs b/architectures/decentralized/solana-client/src/app.rs
index 36a529bbb..dfb242cb0 100644
--- a/architectures/decentralized/solana-client/src/app.rs
+++ b/architectures/decentralized/solana-client/src/app.rs
@@ -11,7 +11,8 @@ use anchor_client::{
 };
 use anyhow::{Result, anyhow};
 use psyche_client::{
-    Client, ClientTUI, ClientTUIState, NC, RunInitConfig, TrainArgs, read_identity_secret_key,
+    Client, ClientTUI, ClientTUIState, ModelExtraData, NC, RunInitConfig, TrainArgs,
+    read_identity_secret_key,
 };
 use psyche_coordinator::{ClientState, Coordinator, CoordinatorError, RunState};
 use psyche_core::sha256;
@@ -90,6 +91,7 @@ pub async fn build_app(
     let eval_tasks = p.eval_tasks()?;
     let hub_read_token = std::env::var("HF_TOKEN").ok();
     let checkpoint_config = p.checkpoint_config()?;
+    let model_extra_data_override: Option<ModelExtraData> = p.model_extra_data_override()?;
 
     let solana_pubkey = wallet_keypair.pubkey();
     let wandb_info = p.wandb_info(format!("{}-{solana_pubkey}", p.run_id))?;
@@ -134,6 +136,7 @@ pub async fn build_app(
             max_concurrent_parameter_requests: p.max_concurrent_parameter_requests,
             device: p.device,
             sidecar_port: p.sidecar_port,
+            model_extra_data_override,
         };
     let app = App {
         run_id: p.run_id.clone(),
diff --git a/architectures/decentralized/solana-client/src/main.rs b/architectures/decentralized/solana-client/src/main.rs
index 547940b8f..d4f45c179 100644
--- a/architectures/decentralized/solana-client/src/main.rs
+++ b/architectures/decentralized/solana-client/src/main.rs
@@ -288,6 +288,9 @@ async fn async_main() -> Result<()> {
                     Checkpoint::Ephemeral => {
                         bail!("Can't predownload model with ephemeral checkpoint.")
                     }
+                    Checkpoint::P2PDummy => {
+                        println!("P2PDummy checkpoint (for testing), nothing to predownload.");
+                    }
                     Checkpoint::Dummy(hub_repo)
                     | Checkpoint::Hub(hub_repo)
                     | Checkpoint::P2P(hub_repo) => {
diff --git a/architectures/decentralized/solana-coordinator/Cargo.lock b/architectures/decentralized/solana-coordinator/Cargo.lock
index 72a38df53..6a1fe747f 100644
--- a/architectures/decentralized/solana-coordinator/Cargo.lock
+++ b/architectures/decentralized/solana-coordinator/Cargo.lock
@@ -1610,6 +1610,7 @@ dependencies = [
  "cfg_eval",
  "psyche-core",
  "serde",
+ "serde_json",
  "serde_with",
  "ts-rs",
 ]
diff --git a/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_data_layout.rs b/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_data_layout.rs
index 8257cbbd1..87e1a26d0 100644
--- a/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_data_layout.rs
+++ b/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_data_layout.rs
@@ -1,19 +1,10 @@
 use psyche_coordinator::Round;
 use psyche_coordinator::RunState;
 use psyche_coordinator::model::Checkpoint;
-use psyche_coordinator::model::HttpTrainingDataLocation;
-use psyche_coordinator::model::LLMArchitecture;
-use psyche_coordinator::model::LLMTrainingDataLocation;
-use psyche_coordinator::model::LLMTrainingDataType;
 use psyche_coordinator::model::Model;
-use psyche_core::CosineLR;
 use psyche_core::FixedString;
 use psyche_core::FixedVec;
-use psyche_core::LearningRateSchedule;
-use psyche_core::OptimizerDefinition;
-use psyche_core::Shuffle;
 use psyche_core::SmallBoolean;
-use psyche_core::TokenSize;
 use psyche_solana_coordinator::CoordinatorAccount;
 use psyche_solana_coordinator::coordinator_account_from_bytes;
 
@@ -43,12 +34,11 @@ pub async fn run() {
     assert_eq!(coordinator.run_state, RunState::Uninitialized);
     assert_eq!(coordinator.run_state_start_unix_timestamp, 0);
     assert_eq!(coordinator.pending_pause, SmallBoolean::FALSE);
-    // Coordinator model
+    // Coordinator model (only on-chain fields)
     match coordinator.model {
         Model::LLM(llm) => {
             assert_eq!(llm.max_seq_len, 2048);
             assert_eq!(llm.cold_start_warmup_steps, 0);
-            assert_eq!(llm.architecture, LLMArchitecture::HfLlama);
             match llm.checkpoint {
                 Checkpoint::Hub(hub) => {
                     assert_eq!(
@@ -59,57 +49,6 @@ pub async fn run() {
                 },
                 _ => panic!("Expected Hub checkpoint"),
             };
-            assert_eq!(llm.data_type, LLMTrainingDataType::Pretraining);
-            match llm.data_location {
-                LLMTrainingDataLocation::Http(http) => {
-                    match http.location {
-                        HttpTrainingDataLocation::Gcp {
-                            bucket_name,
-                            filter_directory,
-                        } => {
-                            assert_eq!(
-                                bucket_name,
-                                fixed_str("nous-pretraining-public-us")
-                            );
-                            assert_eq!(
-                                filter_directory,
-                                fixed_str("fineweb-edu-tokenized-llama2")
-                            );
-                        },
-                        _ => panic!("Expected Gcp data location"),
-                    };
-                    assert_eq!(http.token_size_in_bytes, TokenSize::TwoBytes);
-                    assert_eq!(http.shuffle, Shuffle::DontShuffle);
-                },
-                _ => panic!("Expected Http data location"),
-            };
-            match llm.lr_schedule {
-                LearningRateSchedule::Cosine(learning_rate) => {
-                    assert_eq!(
-                        learning_rate,
-                        CosineLR::new(0.0004, 250, 0.0, 25000, 0.00004)
-                    );
-                },
-                _ => panic!("Expected Constant LR schedule"),
-            };
-            match llm.optimizer {
-                OptimizerDefinition::Distro {
-                    clip_grad_norm,
-                    weight_decay,
-                    compression_decay,
-                    compression_topk,
-                    compression_chunk,
-                    quantize_1bit,
-                } => {
-                    assert_eq!(clip_grad_norm, Some(1.0));
-                    assert_eq!(weight_decay, None);
-                    assert_eq!(compression_decay, 0.999);
-                    assert_eq!(compression_topk, 2);
-                    assert_eq!(compression_chunk, 64);
-                    assert_eq!(quantize_1bit, false);
-                },
-                _ => panic!("Expected Distro optimizer"),
-            }
         },
     };
     // Coordinator config
diff --git a/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_full_round.rs b/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_full_round.rs
index fc03202cf..45a235723 100644
--- a/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_full_round.rs
+++ b/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_full_round.rs
@@ -5,13 +5,7 @@ use psyche_coordinator::WitnessProof;
 use psyche_coordinator::model::Checkpoint;
 use psyche_coordinator::model::HubRepo;
 use psyche_coordinator::model::LLM;
-use psyche_coordinator::model::LLMArchitecture;
-use psyche_coordinator::model::LLMTrainingDataLocation;
-use psyche_coordinator::model::LLMTrainingDataType;
 use psyche_coordinator::model::Model;
-use psyche_core::ConstantLR;
-use psyche_core::LearningRateSchedule;
-use psyche_core::OptimizerDefinition;
 use psyche_solana_authorizer::logic::AuthorizationGrantorUpdateParams;
 use psyche_solana_coordinator::ClientId;
 use psyche_solana_coordinator::CoordinatorAccount;
@@ -111,20 +105,8 @@ pub async fn run() {
             waiting_for_members_extra_time: 3,
         }),
         Some(Model::LLM(LLM {
-            architecture: LLMArchitecture::HfLlama,
             checkpoint: Checkpoint::Dummy(HubRepo::dummy()),
             max_seq_len: 4096,
-            data_type: LLMTrainingDataType::Pretraining,
-            data_location: LLMTrainingDataLocation::default(),
-            lr_schedule: LearningRateSchedule::Constant(ConstantLR::default()),
-            optimizer: OptimizerDefinition::Distro {
-                clip_grad_norm: None,
-                compression_decay: 1.0,
-                compression_topk: 1,
-                compression_chunk: 1,
-                quantize_1bit: false,
-                weight_decay: None,
-            },
             cold_start_warmup_steps: 0,
         })),
         None, // no explicit progress
diff --git a/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_rewards.rs b/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_rewards.rs
index f69bbf8c5..d8779d257 100644
--- a/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_rewards.rs
+++ b/architectures/decentralized/solana-tooling/tests/suites/memnet_coordinator_rewards.rs
@@ -5,13 +5,7 @@ use psyche_coordinator::WAITING_FOR_MEMBERS_EXTRA_SECONDS;
 use psyche_coordinator::model::Checkpoint;
 use psyche_coordinator::model::HubRepo;
 use psyche_coordinator::model::LLM;
-use psyche_coordinator::model::LLMArchitecture;
-use psyche_coordinator::model::LLMTrainingDataLocation;
-use psyche_coordinator::model::LLMTrainingDataType;
 use psyche_coordinator::model::Model;
-use psyche_core::ConstantLR;
-use psyche_core::LearningRateSchedule;
-use psyche_core::OptimizerDefinition;
 use psyche_solana_authorizer::logic::AuthorizationGrantorUpdateParams;
 use psyche_solana_coordinator::ClientId;
 use psyche_solana_coordinator::CoordinatorAccount;
@@ -108,20 +102,8 @@ pub async fn run() {
             total_steps: 100,
         }),
         Some(Model::LLM(LLM {
-            architecture: LLMArchitecture::HfLlama,
             checkpoint: Checkpoint::Dummy(HubRepo::dummy()),
             max_seq_len: 4096,
-            data_type: LLMTrainingDataType::Pretraining,
-            data_location: LLMTrainingDataLocation::default(),
-            lr_schedule: LearningRateSchedule::Constant(ConstantLR::default()),
-            optimizer: OptimizerDefinition::Distro {
-                clip_grad_norm: None,
-                compression_decay: 1.0,
-                compression_topk: 1,
-                compression_chunk: 1,
-                quantize_1bit: false,
-                weight_decay: None,
-            },
             cold_start_warmup_steps: 0,
         })),
         None, // no explicit progress
diff --git a/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_create_update.rs b/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_create_update.rs
index e51ced2dd..3d185f7fd 100644
--- a/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_create_update.rs
+++ b/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_create_update.rs
@@ -3,13 +3,7 @@ use psyche_coordinator::WAITING_FOR_MEMBERS_EXTRA_SECONDS;
 use psyche_coordinator::model::Checkpoint;
 use psyche_coordinator::model::HubRepo;
 use psyche_coordinator::model::LLM;
-use psyche_coordinator::model::LLMArchitecture;
-use psyche_coordinator::model::LLMTrainingDataLocation;
-use psyche_coordinator::model::LLMTrainingDataType;
 use psyche_coordinator::model::Model;
-use psyche_core::ConstantLR;
-use psyche_core::LearningRateSchedule;
-use psyche_core::OptimizerDefinition;
 use psyche_solana_coordinator::CoordinatorAccount;
 use psyche_solana_tooling::create_memnet_endpoint::create_memnet_endpoint;
 use psyche_solana_tooling::process_treasurer_instructions::process_treasurer_run_create;
@@ -55,20 +49,8 @@ pub async fn run() {
                 as u8,
         }),
         model: Some(Model::LLM(LLM {
-            architecture: LLMArchitecture::HfLlama,
             checkpoint: Checkpoint::Dummy(HubRepo::dummy()),
             max_seq_len: 4096,
-            data_type: LLMTrainingDataType::Pretraining,
-            data_location: LLMTrainingDataLocation::default(),
-            lr_schedule: LearningRateSchedule::Constant(ConstantLR::default()),
-            optimizer: OptimizerDefinition::Distro {
-                clip_grad_norm: None,
-                compression_decay: 1.0,
-                compression_topk: 1,
-                compression_chunk: 1,
-                quantize_1bit: false,
-                weight_decay: None,
-            },
             cold_start_warmup_steps: 0,
         })),
         progress: None,
diff --git a/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_full_epoch.rs b/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_full_epoch.rs
index 014772e32..3875de2be 100644
--- a/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_full_epoch.rs
+++ b/architectures/decentralized/solana-tooling/tests/suites/memnet_treasurer_full_epoch.rs
@@ -7,13 +7,7 @@ use psyche_coordinator::WAITING_FOR_MEMBERS_EXTRA_SECONDS;
 use psyche_coordinator::model::Checkpoint;
 use psyche_coordinator::model::HubRepo;
 use psyche_coordinator::model::LLM;
-use psyche_coordinator::model::LLMArchitecture;
-use psyche_coordinator::model::LLMTrainingDataLocation;
-use psyche_coordinator::model::LLMTrainingDataType;
 use psyche_coordinator::model::Model;
-use psyche_core::ConstantLR;
-use psyche_core::LearningRateSchedule;
-use psyche_core::OptimizerDefinition;
 use psyche_solana_authorizer::logic::AuthorizationGranteeUpdateParams;
 use psyche_solana_authorizer::logic::AuthorizationGrantorUpdateParams;
 use psyche_solana_coordinator::ClientId;
@@ -230,22 +224,8 @@ pub async fn run() {
                 waiting_for_members_extra_time: 3,
             }),
             model: Some(Model::LLM(LLM {
-                architecture: LLMArchitecture::HfLlama,
                 checkpoint: Checkpoint::Dummy(HubRepo::dummy()),
                 max_seq_len: 4096,
-                data_type: LLMTrainingDataType::Pretraining,
-                data_location: LLMTrainingDataLocation::default(),
-                lr_schedule: LearningRateSchedule::Constant(
-                    ConstantLR::default(),
-                ),
-                optimizer: OptimizerDefinition::Distro {
-                    clip_grad_norm: None,
-                    compression_decay: 1.0,
-                    compression_topk: 1,
-                    compression_chunk: 1,
-                    quantize_1bit: false,
-                    weight_decay: None,
-                },
                 cold_start_warmup_steps: 0,
             })),
             progress: None,
diff --git a/architectures/decentralized/testing/src/docker_setup.rs b/architectures/decentralized/testing/src/docker_setup.rs
index 4f5a80dd9..6d0f09abd 100644
--- a/architectures/decentralized/testing/src/docker_setup.rs
+++ b/architectures/decentralized/testing/src/docker_setup.rs
@@ -4,7 +4,7 @@ use bollard::{
         Config, CreateContainerOptions, KillContainerOptions, ListContainersOptions,
         RemoveContainerOptions,
     },
-    models::DeviceRequest,
+    models::{DeviceRequest, Mount, MountTypeEnum},
     secret::{ContainerSummary, HostConfig},
 };
 use psyche_core::IntegrationTestLogMarker;
@@ -119,6 +119,24 @@ pub async fn spawn_new_client(docker_client: Arc<Docker>) -> Result<String, Dock
 
     // Setting extra hosts and optionally nvidia request
     let network_name = "test_psyche-test-network";
+
+    // Mount the config file from the host
+    let config_mount = Mount {
+        target: Some("/usr/local/config.toml".to_string()),
+        source: Some(
+            std::env::current_dir()
+                .unwrap()
+                .join("../../../config/solana-test/test-config.toml")
+                .canonicalize()
+                .unwrap()
+                .to_string_lossy()
+                .to_string(),
+        ),
+        typ: Some(MountTypeEnum::BIND),
+        read_only: Some(true),
+        ..Default::default()
+    };
+
     let host_config = if has_gpu {
         // Setting nvidia usage parameters
         let device_request = DeviceRequest {
@@ -132,12 +150,14 @@ pub async fn spawn_new_client(docker_client: Arc<Docker>) -> Result<String, Dock
             device_requests: Some(vec![device_request]),
             extra_hosts: Some(vec!["host.docker.internal:host-gateway".to_string()]),
             network_mode: Some(network_name.to_string()),
+            mounts: Some(vec![config_mount]),
             ..Default::default()
         }
     } else {
         HostConfig {
             extra_hosts: Some(vec!["host.docker.internal:host-gateway".to_string()]),
             network_mode: Some(network_name.to_string()),
+            mounts: Some(vec![config_mount]),
             ..Default::default()
         }
     };
diff --git a/architectures/decentralized/testing/src/utils.rs b/architectures/decentralized/testing/src/utils.rs
index 631b05f52..71fa07abe 100644
--- a/architectures/decentralized/testing/src/utils.rs
+++ b/architectures/decentralized/testing/src/utils.rs
@@ -183,7 +183,7 @@ impl ConfigBuilder {
         // This means that every client is a witness
         self.set_value("config.witness_nodes", 0_u32);
 
-        self.set_value("model.LLM.architecture", self.architecture.clone());
+        self.set_value("model_extra_data.architecture", self.architecture.clone());
         self.set_value("config.global_batch_size_start", self.batch_size);
         self.set_value("config.global_batch_size_end", self.batch_size);
 
diff --git a/config/solana-test/light-config.toml b/config/solana-test/light-config.toml
index eab015342..6d244fb9f 100644
--- a/config/solana-test/light-config.toml
+++ b/config/solana-test/light-config.toml
@@ -15,28 +15,33 @@ total_steps = 25000
 waiting_for_members_extra_time = 3
 
 [model.LLM]
-architecture = "HfLlama"
-data_type = "Pretraining"
 max_seq_len = 2048
 cold_start_warmup_steps = 0
 
 [model.LLM.checkpoint.Hub]
 repo_id = "emozilla/llama2-20m-init"
 
-[model.LLM.data_location.Http]
+[model_extra_data]
+version = 1
+architecture = "HfLlama"
+data_type = "Pretraining"
+
+[model_extra_data.data_location.Http]
 token_size_in_bytes = "TwoBytes"
 shuffle = "DontShuffle"
-[model.LLM.data_location.Http.location.Gcp]
+
+[model_extra_data.data_location.Http.location.Gcp]
 bucket_name = "nous-pretraining-public-us"
 filter_directory = "fineweb-edu-tokenized-llama2"
 
-[model.LLM.lr_schedule.Cosine]
+[model_extra_data.lr_schedule.Cosine]
 base_lr = 4.0e-4
 warmup_steps = 250
 warmup_init_lr = 0.0
 total_steps = 25000
 final_lr = 4.0e-5
-[model.LLM.optimizer.Distro]
+
+[model_extra_data.optimizer.Distro]
 clip_grad_norm = 1.0
 compression_decay = 0.999
 compression_chunk = 64
diff --git a/config/solana-test/nano-config.toml b/config/solana-test/nano-config.toml
index c275feea3..7e3636eb9 100644
--- a/config/solana-test/nano-config.toml
+++ b/config/solana-test/nano-config.toml
@@ -15,8 +15,6 @@ total_steps = 25000
 waiting_for_members_extra_time = 3
 
 [model.LLM]
-architecture = "HfLlama"
-data_type = "Pretraining"
 max_seq_len = 64
 cold_start_warmup_steps = 0
 
@@ -24,21 +22,26 @@ cold_start_warmup_steps = 0
 repo_id = "pefontana/Nano-Llama"
 revision = "cf48eac4944f6e954a3d9c9c30e8c865e64e7d03"
 
-[model.LLM.data_location.Http]
+[model_extra_data]
+version = 1
+architecture = "HfLlama"
+data_type = "Pretraining"
+
+[model_extra_data.data_location.Http]
 token_size_in_bytes = "TwoBytes"
 shuffle = "DontShuffle"
 
-[model.LLM.data_location.Http.location]
+[model_extra_data.data_location.Http.location]
 SingleUrl = "https://huggingface.co/pefontana/Nano-Llama/resolve/main/tiny-ci-dataset/000_tiny-test.ds"
 
-[model.LLM.lr_schedule.Cosine]
+[model_extra_data.lr_schedule.Cosine]
 base_lr = 4.0e-4
 warmup_steps = 250
 warmup_init_lr = 0.0
 total_steps = 25000
 final_lr = 4.0e-5
 
-[model.LLM.optimizer.Distro]
+[model_extra_data.optimizer.Distro]
 clip_grad_norm = 1.0
 compression_decay = 0.999
 compression_chunk = 64
diff --git a/docker/psyche_client_create_run.sh b/docker/psyche_client_create_run.sh
index 9fc6b177a..61474c113 100755
--- a/docker/psyche_client_create_run.sh
+++ b/docker/psyche_client_create_run.sh
@@ -65,7 +65,8 @@ cargo run --release --bin run-manager -- \
     --rpc ${RPC} \
     --ws-rpc ${WS_RPC} \
     --run-id ${RUN_ID} \
-    --config-path "${CONFIG_PATH}"
+    --config-path "${CONFIG_PATH}" \
+    --skip-upload-model-extra-data
 
 echo -e "\n[+] Model config uploaded successfully"
 
diff --git a/docker/test/client_test_entrypoint.sh b/docker/test/client_test_entrypoint.sh
index 64e739841..09d16ec91 100644
--- a/docker/test/client_test_entrypoint.sh
+++ b/docker/test/client_test_entrypoint.sh
@@ -18,6 +18,7 @@ if [ "${PYTHON_ENABLED}" = "true" ]; then
         --run-id "${RUN_ID}" \
         --data-parallelism 8 \
         --sidecar-port "${SIDECAR_PORT}" \
+        --model-extra-data-toml "/usr/local/config.toml" \
         --logs "json"
 else
     echo "Starting client without Python features"
@@ -26,5 +27,6 @@ else
         --rpc "${RPC}" \
         --ws-rpc "${WS_RPC}" \
         --run-id "${RUN_ID}" \
+        --model-extra-data-toml "/usr/local/config.toml" \
         --logs "json"
 fi
diff --git a/docker/test/docker-compose.yml b/docker/test/docker-compose.yml
index 7c209a12a..2832d0834 100644
--- a/docker/test/docker-compose.yml
+++ b/docker/test/docker-compose.yml
@@ -12,6 +12,8 @@ services:
       - '../../config/client/.env.local'
     environment:
       - HF_TOKEN=${HF_TOKEN:-}
+    volumes:
+      - '../../config/solana-test/test-config.toml:/usr/local/config.toml:ro'
     networks:
       - psyche-test-network
 
diff --git a/docker/test/run_owner_entrypoint.sh b/docker/test/run_owner_entrypoint.sh
index 9d6fc9db2..9d8320333 100644
--- a/docker/test/run_owner_entrypoint.sh
+++ b/docker/test/run_owner_entrypoint.sh
@@ -25,7 +25,8 @@ run-manager update-config \
     --rpc "${RPC}" \
     --ws-rpc "${WS_RPC}" \
     --run-id "${RUN_ID}" \
-    --config-path "/usr/local/config.toml"
+    --config-path "/usr/local/config.toml" \
+    --skip-upload-model-extra-data
 
 run-manager set-paused \
     --wallet-private-key-path ${WALLET_FILE} \
diff --git a/docker/test/three_clients_test/docker-compose.yml b/docker/test/three_clients_test/docker-compose.yml
index 0d8958749..86cac62a2 100644
--- a/docker/test/three_clients_test/docker-compose.yml
+++ b/docker/test/three_clients_test/docker-compose.yml
@@ -16,6 +16,8 @@ services:
       - 'host.docker.internal:host-gateway'
     env_file:
       - '../../../config/client/.env.local'
+    volumes:
+      - '../../../config/solana-test/test-config.toml:/usr/local/config.toml:ro'
     networks:
       - psyche-test-network
 
@@ -36,6 +38,8 @@ services:
       - 'host.docker.internal:host-gateway'
     env_file:
       - '../../../config/client/.env.local'
+    volumes:
+      - '../../../config/solana-test/test-config.toml:/usr/local/config.toml:ro'
     networks:
       - psyche-test-network
 
@@ -56,6 +60,8 @@ services:
       - 'host.docker.internal:host-gateway'
     env_file:
       - '../../../config/client/.env.local'
+    volumes:
+      - '../../../config/solana-test/test-config.toml:/usr/local/config.toml:ro'
     networks:
       - psyche-test-network
 
diff --git a/nix/docker.nix b/nix/docker.nix
index acbea1ea5..a50a0b681 100644
--- a/nix/docker.nix
+++ b/nix/docker.nix
@@ -69,9 +69,7 @@ let
             mkdir -p $out/bin
             mkdir -p $out/architectures/decentralized/solana-authorizer/target/deploy
             cp ${../docker/test/client_test_entrypoint.sh} $out/bin/client_test_entrypoint.sh
-            cp ${../docker/test/run_owner_entrypoint.sh} $out/bin/run_owner_entrypoint.sh
             chmod +x $out/bin/client_test_entrypoint.sh
-            chmod +x $out/bin/run_owner_entrypoint.sh
           '')
         ]
         ++ lib.optionals usePython [
diff --git a/scripts/create-permissionless-run.sh b/scripts/create-permissionless-run.sh
index 582974fff..125f62f4b 100755
--- a/scripts/create-permissionless-run.sh
+++ b/scripts/create-permissionless-run.sh
@@ -81,7 +81,8 @@ cargo run --release --bin run-manager -- \
     --run-id ${RUN_ID} \
     --config-path ${CONFIG_FILE} \
     --num-parameters 1100000000 \
-    --vocab-size 32768
+    --vocab-size 32768 \
+    --skip-upload-model-extra-data
 
 echo -e "\n[+] Unpause the training run..."
 cargo run --release --bin run-manager -- \
diff --git a/scripts/setup-test-run.sh b/scripts/setup-test-run.sh
index 20602f509..01f3f387a 100755
--- a/scripts/setup-test-run.sh
+++ b/scripts/setup-test-run.sh
@@ -55,7 +55,8 @@ nix run .#run-manager -- \
     --rpc "${RPC}" \
     --ws-rpc "${WS_RPC}" \
     --run-id "${RUN_ID}" \
-    --config-path "config/solana-test/test-config.toml"
+    --config-path "config/solana-test/test-config.toml" \
+    --skip-upload-model-extra-data
 
 echo "[+] Unpausing run..."
 nix run .#run-manager -- \
diff --git a/scripts/train-solana-test.sh b/scripts/train-solana-test.sh
index 55699e591..4b5986ded 100755
--- a/scripts/train-solana-test.sh
+++ b/scripts/train-solana-test.sh
@@ -30,6 +30,15 @@ DP=${DP:-"8"}
 TP=${TP:-"1"}
 BATCH_SIZE=${BATCH_SIZE:-"1"}
 
+# Optional checkpoint args
+CHECKPOINT_ARGS=()
+if [[ "$CHECKPOINT" == "true" ]]; then
+    echo -e "\n[+] Starting Solana training with checkpointing enabled..."
+    CHECKPOINT_ARGS+=(--skip-checkpoint-upload)
+else
+    echo -e "\n[+] Starting Solana training without checkpointing..."
+fi
+
 # fine if this fails
 solana airdrop 10 "$(solana-keygen pubkey ${WALLET_FILE})" --url "${RPC}" || true
 
@@ -47,6 +56,8 @@ if [[ "$OTLP_METRICS_URL" == "" ]]; then
         --micro-batch-size ${BATCH_SIZE} \
         --authorizer ${AUTHORIZER} \
         --logs "console" \
+        --model-extra-data-toml ./config/solana-test/light-config.toml \
+        ${CHECKPOINT_ARGS[@]} \
         "$@"
 else
     cargo run --release --bin psyche-solana-client -- \
@@ -62,5 +73,7 @@ else
         --authorizer ${AUTHORIZER} \
         --oltp-metrics-url "http://localhost:4318/v1/metrics" \
         --oltp-logs-url "http://localhost:4318/v1/logs" \
+        --model-extra-data-toml ./config/solana-test/light-config.toml \
+        ${CHECKPOINT_ARGS[@]} \
         "$@"
 fi
diff --git a/shared/client/Cargo.toml b/shared/client/Cargo.toml
index 5f7159d81..1249c71d6 100644
--- a/shared/client/Cargo.toml
+++ b/shared/client/Cargo.toml
@@ -18,6 +18,7 @@ postcard.workspace = true
 anyhow.workspace = true
 serde.workspace = true
 serde_json.workspace = true
+toml.workspace = true
 tch.workspace = true
 tokenizers.workspace = true
 tokio.workspace = true
diff --git a/shared/client/src/cli.rs b/shared/client/src/cli.rs
index a4ef145f0..32b4cddc0 100644
--- a/shared/client/src/cli.rs
+++ b/shared/client/src/cli.rs
@@ -1,8 +1,9 @@
 use crate::{CheckpointConfig, WandBInfo};
 
 use crate::UploadInfo;
-use anyhow::{Result, anyhow, bail};
+use anyhow::{Context, Result, anyhow, bail};
 use clap::Args;
+use psyche_coordinator::model_extra_data::ModelExtraData;
 use psyche_data_provider::{GcsUploadInfo, HubUploadInfo};
 use psyche_eval::tasktype_from_name;
 use psyche_modeling::Devices;
@@ -204,6 +205,11 @@ pub struct TrainArgs {
 
     #[clap(long, default_value_t = 3, env)]
     pub keep_steps: u32,
+
+    /// Path to a TOML config file. If provided, uses this config instead of fetching from the remote repo.
+    /// Only meant for testing/debugging.
+    #[clap(long, env, hide = true)]
+    pub model_extra_data_toml: Option<PathBuf>,
 }
 
 impl TrainArgs {
@@ -327,6 +333,32 @@ impl TrainArgs {
             .collect();
         result
     }
+
+    pub fn model_extra_data_override(&self) -> Result<Option<ModelExtraData>> {
+        let Some(path) = &self.model_extra_data_toml else {
+            return Ok(None);
+        };
+
+        let content = std::fs::read_to_string(path)
+            .with_context(|| format!("failed to read model extra data TOML file {:?}", path))?;
+
+        let toml_value: toml::Value = toml::from_str(&content)
+            .with_context(|| format!("failed to parse TOML file {:?}", path))?;
+
+        let model_extra_data_table = toml_value
+            .get("model_extra_data")
+            .ok_or_else(|| anyhow::anyhow!("missing [model_extra_data] section in {:?}", path))?;
+
+        let config: ModelExtraData =
+            model_extra_data_table.clone().try_into().with_context(|| {
+                format!(
+                    "failed to deserialize model_extra_data from TOML file {:?}",
+                    path
+                )
+            })?;
+
+        Ok(Some(config))
+    }
 }
 
 pub fn prepare_environment() {
diff --git a/shared/client/src/lib.rs b/shared/client/src/lib.rs
index bdad43e30..998795c35 100644
--- a/shared/client/src/lib.rs
+++ b/shared/client/src/lib.rs
@@ -9,8 +9,8 @@ pub use cli::{TrainArgs, prepare_environment, print_identity_keys, read_identity
 pub use client::Client;
 pub use protocol::{Broadcast, BroadcastType, Finished, NC, TrainingResult};
 pub use state::{
-    CheckpointConfig, GcsUploadInfo, HubUploadInfo, InitRunError, RoundState, RunInitConfig,
-    RunInitConfigAndIO, UploadInfo,
+    CheckpointConfig, GcsUploadInfo, HubUploadInfo, InitRunError, ModelExtraData, RoundState,
+    RunInitConfig, RunInitConfigAndIO, UploadInfo,
 };
 pub use tui::{ClientTUI, ClientTUIState};
 
diff --git a/shared/client/src/state/init.rs b/shared/client/src/state/init.rs
index 7a945f74b..0484e795b 100644
--- a/shared/client/src/state/init.rs
+++ b/shared/client/src/state/init.rs
@@ -1,7 +1,9 @@
 use crate::{WandBInfo, fetch_data::DataFetcher};
+pub use psyche_coordinator::model_extra_data::ModelExtraData;
 use psyche_coordinator::{
     Coordinator, HealthChecks,
     model::{self, HttpLLMTrainingDataLocation, LLMTrainingDataLocation},
+    model_extra_data::{CONFIG_PREFIX, MODEL_CONFIG_FILENAME},
 };
 use psyche_core::{
     Barrier, CancellableBarrier, IntegrationTestLogMarker, NodeIdentity, Shuffle, TokenSize,
@@ -9,7 +11,8 @@ use psyche_core::{
 use psyche_data_provider::{
     DataProvider, DataProviderTcpClient, DownloadError, DummyDataProvider,
     PreprocessedDataProvider, Split, WeightedDataProvider, download_dataset_repo_async,
-    download_model_from_gcs_async, download_model_repo_async,
+    download_model_from_gcs_async, download_model_repo_async, fetch_json_from_gcs,
+    fetch_json_from_hub,
     http::{FileURLs, HttpDataProvider},
 };
 use psyche_metrics::ClientMetrics;
@@ -75,6 +78,10 @@ pub struct RunInitConfig<T: NodeIdentity, A: AuthenticatableIdentity> {
     pub dummy_training_delay_secs: Option<u64>,
 
     pub sidecar_port: Option<u16>,
+
+    /// If provided, use this model extra data instead of fetching from GCS/Hub.
+    /// Only meant for testing/debugging.
+    pub model_extra_data_override: Option<ModelExtraData>,
 }
 
 #[derive(Debug, Error)]
@@ -199,11 +206,57 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
 
         let model::Model::LLM(llm) = state.model;
 
+        // Use model extra data override if provided (only meant for testing/debugging),
+        // otherwise fetch from GCS/Hub
+        let model_extra_data: ModelExtraData = if let Some(config) =
+            init_config.model_extra_data_override.clone()
+        {
+            info!("Using model extra data override from CLI");
+            config
+        } else {
+            match llm.checkpoint {
+                model::Checkpoint::Gcs(gcs_repo) | model::Checkpoint::P2PGcs(gcs_repo) => {
+                    let bucket = gcs_repo.bucket.to_string();
+                    let path = format!("{}/{}", CONFIG_PREFIX, MODEL_CONFIG_FILENAME);
+                    debug!("Fetching model extra data from gs://{}/{}", bucket, path);
+                    fetch_json_from_gcs(&bucket, &path).await?
+                }
+                model::Checkpoint::Hub(repo) | model::Checkpoint::P2P(repo) => {
+                    let repo_id: String = (&repo.repo_id).into();
+                    let revision = repo.revision.map(|bytes| (&bytes).into());
+                    let path = format!("{}/{}", CONFIG_PREFIX, MODEL_CONFIG_FILENAME);
+                    debug!("Fetching model extra data from Hub: {}/{}", repo_id, path);
+                    match fetch_json_from_hub(
+                        &repo_id,
+                        revision,
+                        &path,
+                        init_config.hub_read_token.clone(),
+                    )
+                    .await
+                    {
+                        Ok(config) => config,
+                        Err(e) => {
+                            error!(
+                                "Failed to fetch model extra data from Hub ({}), using default: {}",
+                                repo_id, e
+                            );
+                            return Err(InitRunError::GcsModelLoad(e));
+                        }
+                    }
+                }
+                // Dummy/Ephemeral checkpoints use default model extra data (for testing)
+                _ => ModelExtraData::default(),
+            }
+        };
+
         let hub_read_token = init_config.hub_read_token.clone();
         let hub_max_concurrent_downloads = init_config.hub_max_concurrent_downloads;
         let data_future = async {
-            debug!("Setting up data provider from {:?}", llm.data_location);
-            let data_provider = match llm.data_location {
+            debug!(
+                "Setting up data provider from {:?}",
+                model_extra_data.data_location
+            );
+            let data_provider = match model_extra_data.data_location {
                 LLMTrainingDataLocation::Server(data_server) => DataProvider::Server(
                     DataProviderTcpClient::connect(
                         (&data_server).into(),
@@ -268,7 +321,8 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
             Ok(data_provider)
         };
 
-        let model_future: JoinHandle<Result<RawLoadedModel, InitRunError>> = match &llm.architecture
+        let model_future: JoinHandle<Result<RawLoadedModel, InitRunError>> = match &model_extra_data
+            .architecture
         {
             model::LLMArchitecture::HfLlama
             | model::LLMArchitecture::HfDeepseek
@@ -317,6 +371,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                 }),
                 model::Checkpoint::Hub(_)
                 | model::Checkpoint::P2P(_)
+                | model::Checkpoint::P2PDummy
                 | model::Checkpoint::P2PGcs(_)
                 | model::Checkpoint::Gcs(_) => {
                     let checkpoint = llm.checkpoint;
@@ -374,7 +429,9 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                     checkpoint_extra_files,
                                 )
                             }
-                            model::Checkpoint::P2P(_) | model::Checkpoint::P2PGcs(_) => {
+                            model::Checkpoint::P2P(_)
+                            | model::Checkpoint::P2PDummy
+                            | model::Checkpoint::P2PGcs(_) => {
                                 let (tx_model_config_response, rx_model_config_response) =
                                     oneshot::channel();
                                 info!("Checkpoint is p2p, requesting model config over network");
@@ -387,7 +444,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                     rx_model_config_response.await.unwrap();
                                 debug!("Got p2p info, model_config: {}", model_config);
 
-                                let model_config = match llm.architecture {
+                                let model_config = match model_extra_data.architecture {
                                     model::LLMArchitecture::HfLlama => {
                                         AutoConfig::Llama(serde_json::from_str(&model_config)?)
                                     }
@@ -408,7 +465,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                         #[cfg(not(feature = "python"))]
                                         {
                                             return Err(InitRunError::UnsupportedArchitecture(
-                                                llm.architecture.to_string(),
+                                                model_extra_data.architecture.to_string(),
                                             ));
                                         }
                                     }
@@ -479,7 +536,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                             init_config.eval_task_max_docs,
                             // if doing python fsdp we only have one effective dp rank for inference
                             if init_config.data_parallelism > 1
-                                && llm.architecture == model::LLMArchitecture::HfAuto
+                                && model_extra_data.architecture == model::LLMArchitecture::HfAuto
                             {
                                 1
                             } else {
@@ -489,7 +546,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
 
                         let serialized_config = source.serialize_config()?;
                         let attn_implementation: Option<AttentionImplementation> =
-                            match llm.data_type {
+                            match model_extra_data.data_type {
                                 model::LLMTrainingDataType::Finetuning => {
                                     #[cfg(feature = "parallelism")]
                                     {
@@ -503,7 +560,9 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                 model::LLMTrainingDataType::Pretraining => None,
                             };
 
-                        let raw_loaded_model_type: RawLoadedModelType = match llm.architecture {
+                        let raw_loaded_model_type: RawLoadedModelType = match model_extra_data
+                            .architecture
+                        {
                             model::LLMArchitecture::HfAuto | model::LLMArchitecture::Torchtitan => {
                                 #[cfg(feature = "python")]
                                 {
@@ -513,7 +572,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                     tokio::task::spawn_blocking(move || {
                                         if tp != 1 || dp != 1 {
                                             psyche_modeling::PythonDistributedCausalLM::new(
-                                                llm.architecture.to_string(),
+                                                model_extra_data.architecture.to_string(),
                                                 source.try_into()?,
                                                 tch::Device::cuda_if_available(),
                                                 attn_implementation.unwrap_or_default(),
@@ -535,7 +594,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                                     )
                                                 })?;
                                             psyche_modeling::PythonCausalLM::new(
-                                                &llm.architecture.to_string(),
+                                                &model_extra_data.architecture.to_string(),
                                                 &source.try_into()?,
                                                 device,
                                                 attn_implementation.unwrap_or_default(),
@@ -553,7 +612,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                 #[cfg(not(feature = "python"))]
                                 {
                                     return Err(InitRunError::UnsupportedArchitecture(
-                                        llm.architecture.to_string(),
+                                        model_extra_data.architecture.to_string(),
                                     ));
                                 }
                             }
@@ -789,8 +848,8 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                                 barrier,
                                 data_parallel,
                             },
-                            llm.lr_schedule,
-                            llm.optimizer,
+                            model_extra_data.lr_schedule,
+                            model_extra_data.optimizer,
                             init_config.micro_batch_size,
                             init_config.optim_stats_every_n_steps,
                             init_config.grad_accum_in_fp32,
@@ -808,8 +867,8 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                             barrier: Arc::new(psyche_modeling::NopBarrier) as Arc<dyn Barrier>,
                             data_parallel: None,
                         },
-                        llm.lr_schedule,
-                        llm.optimizer,
+                        model_extra_data.lr_schedule,
+                        model_extra_data.optimizer,
                         init_config.micro_batch_size,
                         init_config.optim_stats_every_n_steps,
                         init_config.grad_accum_in_fp32,
@@ -822,8 +881,8 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
                 vec![
                     psyche_modeling::PythonDistributedTrainer::new(
                         model,
-                        llm.lr_schedule,
-                        llm.optimizer,
+                        model_extra_data.lr_schedule,
+                        model_extra_data.optimizer,
                         init_config.micro_batch_size,
                         init_config.optim_stats_every_n_steps,
                         init_config.grad_accum_in_fp32,
@@ -838,7 +897,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
         let stats_logger = StatsLogger::new(
             tokenizer,
             model_task_runner.clone(),
-            llm.lr_schedule,
+            model_extra_data.lr_schedule,
             wandb_run,
             metrics,
         );
@@ -847,6 +906,11 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
             model_task_runner: model_task_runner.clone(),
         };
 
+        let quantize_1bit = match model_extra_data.optimizer {
+            psyche_core::OptimizerDefinition::Distro { quantize_1bit, .. } => quantize_1bit,
+            _ => false,
+        };
+
         let training = TrainingStepMetadata {
             data_fetcher,
             identity: init_config.identity,
@@ -855,6 +919,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> RunInitConfigAndIO<T
             tx_distro_result,
 
             model_task_runner: model_task_runner.clone(),
+            quantize_1bit,
         };
 
         let witness = WitnessStepMetadata {
diff --git a/shared/client/src/state/mod.rs b/shared/client/src/state/mod.rs
index 78e6cd1eb..547bb6fef 100644
--- a/shared/client/src/state/mod.rs
+++ b/shared/client/src/state/mod.rs
@@ -13,7 +13,7 @@ mod train;
 mod warmup;
 mod witness;
 
-pub use init::{InitRunError, RunInitConfig, RunInitConfigAndIO};
+pub use init::{InitRunError, ModelExtraData, RunInitConfig, RunInitConfigAndIO};
 pub use psyche_data_provider::{GcsUploadInfo, HubUploadInfo};
 pub use round_state::RoundState;
 pub use steps::{ApplyMessageOutcome, RunManager};
diff --git a/shared/client/src/state/train.rs b/shared/client/src/state/train.rs
index c759e91cc..1ee77448f 100644
--- a/shared/client/src/state/train.rs
+++ b/shared/client/src/state/train.rs
@@ -8,7 +8,7 @@ use psyche_coordinator::{
     BLOOM_FALSE_RATE, Commitment, CommitteeSelection, Coordinator, CoordinatorError, HealthChecks,
     assign_data_for_state, get_batch_ids_for_node, get_batch_ids_for_round, model,
 };
-use psyche_core::{BatchId, Bloom, IntegrationTestLogMarker, NodeIdentity, OptimizerDefinition};
+use psyche_core::{BatchId, Bloom, IntegrationTestLogMarker, NodeIdentity};
 use psyche_modeling::{
     ApplyDistroResultError, Batch, BatchData, DistroResult, TrainOutput, Trainer,
     TrainerThreadCommunicationError,
@@ -99,6 +99,7 @@ pub struct TrainingStepMetadata<T: NodeIdentity, A: AuthenticatableIdentity> {
     pub write_gradients_dir: Option<PathBuf>,
 
     pub model_task_runner: ModelTaskRunner,
+    pub quantize_1bit: bool,
 }
 
 #[derive(Debug)]
@@ -274,12 +275,7 @@ impl<T: NodeIdentity, A: AuthenticatableIdentity + 'static> TrainingStepMetadata
                 let cancel_training = cancel_training.clone();
                 let write_gradients_dir = self.write_gradients_dir.clone();
                 let tx_distro_result = self.tx_distro_result.clone();
-                let quantize = match &state.model {
-                    model::Model::LLM(llm) => match llm.optimizer {
-                        OptimizerDefinition::Distro { quantize_1bit, .. } => quantize_1bit,
-                        _ => false,
-                    },
-                };
+                let quantize = self.quantize_1bit;
                 let finished = finished.clone();
 
                 let TrainingDataForStep {
diff --git a/shared/coordinator/Cargo.toml b/shared/coordinator/Cargo.toml
index f7cdecc81..2ca5ec09a 100644
--- a/shared/coordinator/Cargo.toml
+++ b/shared/coordinator/Cargo.toml
@@ -9,6 +9,7 @@ async-trait.workspace = true
 anchor-lang.workspace = true
 bytemuck.workspace = true
 serde_with.workspace = true
+serde_json.workspace = true
 serde.workspace = true
 cfg_eval = "0.1.2"
 ts-rs.workspace = true
diff --git a/shared/coordinator/src/coordinator.rs b/shared/coordinator/src/coordinator.rs
index c726655e2..7db9a8f6d 100644
--- a/shared/coordinator/src/coordinator.rs
+++ b/shared/coordinator/src/coordinator.rs
@@ -1,6 +1,6 @@
 use crate::{
     Commitment, Committee, CommitteeProof, CommitteeSelection, WitnessProof,
-    model::{Checkpoint, Model},
+    model::{Checkpoint, HubRepo, Model},
 };
 
 use anchor_lang::{AnchorDeserialize, AnchorSerialize, InitSpace, prelude::borsh};
@@ -936,6 +936,7 @@ impl<T: NodeIdentity> Coordinator<T> {
                 match llm.checkpoint {
                     Checkpoint::P2P(hub_repo) => llm.checkpoint = Checkpoint::Hub(hub_repo),
                     Checkpoint::P2PGcs(gcs_repo) => llm.checkpoint = Checkpoint::Gcs(gcs_repo),
+                    Checkpoint::P2PDummy => llm.checkpoint = Checkpoint::Dummy(HubRepo::dummy()),
                     _ => {}
                 }
             }
@@ -1065,9 +1066,8 @@ impl<T: NodeIdentity> Coordinator<T> {
             // we've completed an epoch, switch to P2P from now on
             let Model::LLM(llm) = &mut self.model;
             match llm.checkpoint {
-                Checkpoint::Hub(hub_repo) | Checkpoint::Dummy(hub_repo) => {
-                    llm.checkpoint = Checkpoint::P2P(hub_repo)
-                }
+                Checkpoint::Hub(hub_repo) => llm.checkpoint = Checkpoint::P2P(hub_repo),
+                Checkpoint::Dummy(_) => llm.checkpoint = Checkpoint::P2PDummy,
                 Checkpoint::Gcs(gcs_repo) => llm.checkpoint = Checkpoint::P2PGcs(gcs_repo),
                 _ => {}
             }
diff --git a/shared/coordinator/src/lib.rs b/shared/coordinator/src/lib.rs
index bef26863e..aae450fb0 100644
--- a/shared/coordinator/src/lib.rs
+++ b/shared/coordinator/src/lib.rs
@@ -5,6 +5,7 @@ mod committee_selection;
 mod coordinator;
 mod data_selection;
 pub mod model;
+pub mod model_extra_data;
 
 pub use commitment::Commitment;
 pub use committee_selection::{
diff --git a/shared/coordinator/src/model.rs b/shared/coordinator/src/model.rs
index 3176f276e..5d3dbb958 100644
--- a/shared/coordinator/src/model.rs
+++ b/shared/coordinator/src/model.rs
@@ -5,10 +5,7 @@ use anchor_lang::{
     prelude::{borsh, msg},
 };
 use bytemuck::{Zeroable, ZeroableInOption};
-use psyche_core::{
-    ConstantLR, FixedString, FixedVec, LearningRateSchedule, OptimizerDefinition, Shuffle,
-    TokenSize,
-};
+use psyche_core::{FixedString, FixedVec, Shuffle, TokenSize};
 use serde::{Deserialize, Serialize};
 use ts_rs::TS;
 
@@ -190,24 +187,14 @@ pub enum HttpTrainingDataLocation {
 pub struct LLM {
     pub max_seq_len: u32,
     pub cold_start_warmup_steps: u32,
-    pub architecture: LLMArchitecture,
     pub checkpoint: Checkpoint,
-    pub data_type: LLMTrainingDataType,
-    pub data_location: LLMTrainingDataLocation,
-    pub lr_schedule: LearningRateSchedule,
-    pub optimizer: OptimizerDefinition,
 }
 
 impl LLM {
     pub fn dummy() -> Self {
         Self {
-            architecture: LLMArchitecture::HfLlama,
             checkpoint: Checkpoint::Dummy(HubRepo::dummy()),
-            data_location: LLMTrainingDataLocation::default(),
-            data_type: LLMTrainingDataType::Pretraining,
-            lr_schedule: LearningRateSchedule::Constant(ConstantLR::default()),
             max_seq_len: 2048,
-            optimizer: OptimizerDefinition::Dummy,
             cold_start_warmup_steps: 0,
         }
     }
@@ -283,6 +270,8 @@ pub enum Checkpoint {
     Dummy(HubRepo),
     Hub(HubRepo),
     P2P(HubRepo),
+    /// P2P checkpoint that originated from a Dummy checkpoint (for testing)
+    P2PDummy,
     Gcs(GcsRepo),
     P2PGcs(GcsRepo),
 }
@@ -290,7 +279,7 @@ pub enum Checkpoint {
 impl std::fmt::Display for Checkpoint {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            Checkpoint::Dummy(_hub_repo) => write!(f, "Dummy"),
+            Checkpoint::Dummy(_) | Checkpoint::P2PDummy => write!(f, "Dummy"),
             Checkpoint::Ephemeral => write!(f, "Ephemeral"),
             Checkpoint::Hub(hub_repo) => write!(f, "{}", &hub_repo.repo_id),
             Checkpoint::P2P(hub_repo) => {
@@ -313,30 +302,8 @@ impl Model {
                     return false;
                 }
 
-                let bad_data_location = match llm.data_location {
-                    LLMTrainingDataLocation::Dummy => false,
-                    LLMTrainingDataLocation::Server(url) => url.is_empty(),
-                    LLMTrainingDataLocation::Local(_) => false,
-                    LLMTrainingDataLocation::Http(HttpLLMTrainingDataLocation {
-                        location, ..
-                    }) => match location {
-                        HttpTrainingDataLocation::SingleUrl(url) => url.is_empty(),
-                        HttpTrainingDataLocation::NumberedFiles {
-                            url_template,
-                            num_files,
-                            ..
-                        } => url_template.is_empty() || num_files == 0,
-                        HttpTrainingDataLocation::Gcp { bucket_name, .. } => bucket_name.is_empty(),
-                    },
-                    LLMTrainingDataLocation::WeightedHttp(url) => url.is_empty(),
-                    LLMTrainingDataLocation::Preprocessed(url) => url.is_empty(),
-                };
-                if bad_data_location {
-                    msg!("model check failed: bad LLM training data location.");
-                    return false;
-                }
                 let bad_checkpoint = match llm.checkpoint {
-                    Checkpoint::Dummy(_hub_repo) => false,
+                    Checkpoint::Dummy(_) | Checkpoint::P2PDummy => false,
                     Checkpoint::Ephemeral => true,
                     Checkpoint::Hub(hub_repo) => hub_repo.repo_id.is_empty(),
                     Checkpoint::P2P(hub_repo) => hub_repo.repo_id.is_empty(),
@@ -349,14 +316,7 @@ impl Model {
                     msg!("model check failed: bad checkpoint");
                     return false;
                 }
-                if !match llm.optimizer {
-                    OptimizerDefinition::Dummy => false,
-                    OptimizerDefinition::AdamW { .. } => true,
-                    OptimizerDefinition::Distro { .. } => true,
-                } {
-                    msg!("model check failed: bad optimizer");
-                    return false;
-                }
+
                 true
             }
         }
diff --git a/shared/coordinator/src/model_extra_data.rs b/shared/coordinator/src/model_extra_data.rs
new file mode 100644
index 000000000..23b68b0de
--- /dev/null
+++ b/shared/coordinator/src/model_extra_data.rs
@@ -0,0 +1,106 @@
+use serde::{Deserialize, Serialize};
+
+use crate::model::{LLMArchitecture, LLMTrainingDataLocation, LLMTrainingDataType};
+use psyche_core::{LearningRateSchedule, OptimizerDefinition};
+
+/// Path within the bucket where config is stored
+pub const CONFIG_PREFIX: &str = "config";
+/// Filename for the model config
+pub const MODEL_CONFIG_FILENAME: &str = "model_config.json";
+
+/// Extra model data that is stored off-chain and fetched by clients.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ModelExtraData {
+    #[serde(default)]
+    pub version: u32,
+
+    pub architecture: LLMArchitecture,
+
+    pub data_type: LLMTrainingDataType,
+
+    pub data_location: LLMTrainingDataLocation,
+
+    pub lr_schedule: LearningRateSchedule,
+
+    pub optimizer: OptimizerDefinition,
+
+    /// Optional run metadata
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub run_metadata: Option<RunMetadata>,
+}
+
+impl Default for ModelExtraData {
+    fn default() -> Self {
+        Self {
+            version: 1,
+            architecture: LLMArchitecture::HfLlama,
+            data_type: LLMTrainingDataType::Pretraining,
+            data_location: LLMTrainingDataLocation::default(),
+            lr_schedule: LearningRateSchedule::Constant(psyche_core::ConstantLR::default()),
+            optimizer: OptimizerDefinition::Dummy,
+            run_metadata: None,
+        }
+    }
+}
+
+/// Run metadata - display information about the run
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct RunMetadata {
+    #[serde(default)]
+    pub name: String,
+
+    #[serde(default)]
+    pub description: String,
+
+    #[serde(default)]
+    pub num_parameters: u64,
+
+    #[serde(default)]
+    pub vocab_size: u64,
+
+    #[serde(default)]
+    pub client_version: String,
+}
+
+impl ModelExtraData {
+    pub fn to_json(&self) -> Result<String, serde_json::Error> {
+        serde_json::to_string_pretty(self)
+    }
+
+    pub fn from_json(json: &str) -> Result<Self, serde_json::Error> {
+        serde_json::from_str(json)
+    }
+
+    /// Validate the configuration
+    pub fn check(&self) -> bool {
+        let bad_data_location = match &self.data_location {
+            LLMTrainingDataLocation::Dummy => false,
+            LLMTrainingDataLocation::Server(url) => url.is_empty(),
+            LLMTrainingDataLocation::Local(_) => false,
+            LLMTrainingDataLocation::Http(http_loc) => {
+                use crate::model::HttpTrainingDataLocation;
+                match &http_loc.location {
+                    HttpTrainingDataLocation::SingleUrl(url) => url.is_empty(),
+                    HttpTrainingDataLocation::NumberedFiles {
+                        url_template,
+                        num_files,
+                        ..
+                    } => url_template.is_empty() || *num_files == 0,
+                    HttpTrainingDataLocation::Gcp { bucket_name, .. } => bucket_name.is_empty(),
+                }
+            }
+            LLMTrainingDataLocation::WeightedHttp(url) => url.is_empty(),
+            LLMTrainingDataLocation::Preprocessed(url) => url.is_empty(),
+        };
+
+        if bad_data_location {
+            return false;
+        }
+
+        match &self.optimizer {
+            OptimizerDefinition::Dummy => false,
+            OptimizerDefinition::AdamW { .. } => true,
+            OptimizerDefinition::Distro { .. } => true,
+        }
+    }
+}
diff --git a/shared/data-provider/src/errors.rs b/shared/data-provider/src/errors.rs
index b84bc5f9a..d2afa5ce7 100644
--- a/shared/data-provider/src/errors.rs
+++ b/shared/data-provider/src/errors.rs
@@ -26,6 +26,9 @@ pub enum UploadError {
     #[error("GCS operation failed: {0}")]
     GcsStorage(#[from] google_cloud_storage::http::Error),
 
+    #[error("GCS error: {0}")]
+    Gcs(String),
+
     // Common errors
     #[error("IO error: {0}")]
     Io(#[from] std::io::Error),
@@ -45,6 +48,9 @@ pub enum DownloadError {
     #[error("GCS operation failed: {0}")]
     GcsStorage(#[from] google_cloud_storage::http::Error),
 
+    #[error("GCS error: {0}")]
+    Gcs(String),
+
     #[error("IO error: {0}")]
     Io(#[from] std::io::Error),
 
diff --git a/shared/data-provider/src/gcs.rs b/shared/data-provider/src/gcs.rs
index 71f29e414..ddd31e0b3 100644
--- a/shared/data-provider/src/gcs.rs
+++ b/shared/data-provider/src/gcs.rs
@@ -323,6 +323,69 @@ pub fn download_model_from_gcs_sync(
     rt.block_on(download_model_from_gcs_async(bucket, prefix))
 }
 
+/// Fetch a JSON file from GCS and deserialize it.
+/// Used for fetching external model configuration.
+pub async fn fetch_json_from_gcs<T: serde::de::DeserializeOwned>(
+    bucket: &str,
+    object_path: &str,
+) -> Result<T, DownloadError> {
+    // Use authenticated client if GOOGLE_APPLICATION_CREDENTIALS is set, otherwise anonymous
+    let config = if std::env::var("GOOGLE_APPLICATION_CREDENTIALS").is_ok() {
+        info!("Using authenticated GCS client for config fetch");
+        ClientConfig::default().with_auth().await?
+    } else {
+        info!("Using anonymous GCS client for config fetch");
+        ClientConfig::default().anonymous()
+    };
+    let client = Client::new(config);
+
+    info!("Fetching gs://{}/{}", bucket, object_path);
+
+    let data = client
+        .download_object(
+            &GetObjectRequest {
+                bucket: bucket.to_owned(),
+                object: object_path.to_owned(),
+                ..Default::default()
+            },
+            &Range::default(),
+        )
+        .await?;
+
+    serde_json::from_slice(&data).map_err(DownloadError::Json)
+}
+
+/// Upload a JSON-serializable value to GCS.
+pub async fn upload_json_to_gcs<T: serde::Serialize>(
+    bucket: &str,
+    object_path: &str,
+    value: &T,
+) -> Result<(), UploadError> {
+    // Use authenticated client - must have credentials for upload
+    let config = ClientConfig::default().with_auth().await?;
+    let client = Client::new(config);
+
+    let json = serde_json::to_string_pretty(value)?;
+    let data = json.into_bytes();
+
+    info!("Uploading JSON to gs://{}/{}", bucket, object_path);
+
+    client
+        .upload_object(
+            &UploadObjectRequest {
+                bucket: bucket.to_owned(),
+                ..Default::default()
+            },
+            data,
+            &UploadType::Simple(Media::new(object_path.to_owned())),
+        )
+        .await?;
+
+    info!("Uploaded JSON to gs://{}/{}", bucket, object_path);
+
+    Ok(())
+}
+
 pub async fn upload_to_gcs(
     gcs_info: GcsUploadInfo,
     manifest_metadata: GcsManifestMetadata,
diff --git a/shared/data-provider/src/hub.rs b/shared/data-provider/src/hub.rs
index 13a575b84..c38236460 100644
--- a/shared/data-provider/src/hub.rs
+++ b/shared/data-provider/src/hub.rs
@@ -1,4 +1,4 @@
-use crate::errors::UploadError;
+use crate::errors::{DownloadError, UploadError};
 use crate::hub::model::HubRepo;
 use hf_hub::{
     Cache, Repo, RepoType,
@@ -8,10 +8,11 @@ use hf_hub::{
     },
 };
 use psyche_coordinator::model;
+use psyche_coordinator::model_extra_data::ModelExtraData;
 use psyche_core::FixedString;
 use std::{path::PathBuf, time::Instant};
 use tokio::sync::mpsc;
-use tracing::{error, info};
+use tracing::{debug, error, info};
 
 const MODEL_EXTENSIONS: [&str; 3] = [".safetensors", ".json", ".py"];
 const DATASET_EXTENSIONS: [&str; 1] = [".parquet"];
@@ -193,6 +194,73 @@ pub fn download_dataset_repo_sync(
     )
 }
 
+/// Fetch a JSON file from HuggingFace and deserialize it.
+/// Used for fetching external model configuration from Hub.
+pub async fn fetch_json_from_hub<T: serde::de::DeserializeOwned>(
+    repo_id: &str,
+    revision: Option<String>,
+    filename: &str,
+    token: Option<String>,
+) -> Result<T, DownloadError> {
+    let cache = Cache::default();
+    let api = hf_hub::api::tokio::ApiBuilder::new()
+        .with_cache_dir(cache.path().clone())
+        .with_token(token.or(cache.token()))
+        .with_progress(false)
+        .build()?;
+
+    let repo = match revision {
+        Some(rev) => Repo::with_revision(repo_id.to_string(), RepoType::Model, rev),
+        None => Repo::model(repo_id.to_string()),
+    };
+    let api_repo = api.repo(repo);
+
+    debug!("Fetching {} from {}", filename, repo_id);
+
+    let file_path = api_repo.get(filename).await?;
+    let content = tokio::fs::read_to_string(&file_path).await?;
+
+    serde_json::from_str(&content).map_err(DownloadError::Json)
+}
+
+/// Upload model extra data to HuggingFace Hub.
+pub async fn upload_model_extra_data_to_hub(
+    repo_id: &str,
+    filename: &str,
+    model_extra_data: &ModelExtraData,
+    token: Option<String>,
+    commit_message: Option<String>,
+) -> Result<(), UploadError> {
+    let cache = Cache::default();
+    let api = hf_hub::api::tokio::ApiBuilder::new()
+        .with_cache_dir(cache.path().clone())
+        .with_token(token.or(cache.token()))
+        .with_progress(false)
+        .build()?;
+
+    let repo = Repo::model(repo_id.to_string());
+    let api_repo = api.repo(repo);
+
+    let json = serde_json::to_string_pretty(model_extra_data)?;
+    let data = json.into_bytes();
+
+    info!("Uploading JSON to {}/{} on HuggingFace", repo_id, filename);
+
+    api_repo
+        .upload_file(
+            UploadSource::Bytes(data),
+            filename,
+            commit_message.or_else(|| Some(format!("Upload {}", filename))),
+            None,
+            false,
+        )
+        .await?;
+
+    info!("Uploaded JSON to {}/{} on HuggingFace", repo_id, filename);
+
+    Ok(())
+}
+
 #[derive(Debug, Clone)]
 pub struct HubUploadInfo {
     pub hub_repo: String,
diff --git a/shared/data-provider/src/lib.rs b/shared/data-provider/src/lib.rs
index 0044d77d2..8899313e3 100644
--- a/shared/data-provider/src/lib.rs
+++ b/shared/data-provider/src/lib.rs
@@ -19,11 +19,13 @@ pub use errors::{DownloadError, UploadError};
 pub use file_extensions::{DATA_FILE_EXTENSIONS, PARQUET_EXTENSION};
 pub use gcs::{
     GcsCheckpointManifest, GcsManifestMetadata, GcsUploadInfo, ManifestFileEntry, ManifestMetadata,
-    download_model_from_gcs_async, download_model_from_gcs_sync, upload_to_gcs,
+    download_model_from_gcs_async, download_model_from_gcs_sync, fetch_json_from_gcs,
+    upload_json_to_gcs, upload_to_gcs,
 };
 pub use hub::{
     HubUploadInfo, download_dataset_repo_async, download_dataset_repo_sync,
-    download_model_repo_async, download_model_repo_sync, upload_to_hub,
+    download_model_repo_async, download_model_repo_sync, fetch_json_from_hub,
+    upload_model_extra_data_to_hub, upload_to_hub,
 };
 pub use local::LocalDataProvider;
 pub use parquet::record::{ListAccessor, MapAccessor, RowAccessor};
diff --git a/shared/watcher/src/tui.rs b/shared/watcher/src/tui.rs
index 58bac18ba..b95272cca 100644
--- a/shared/watcher/src/tui.rs
+++ b/shared/watcher/src/tui.rs
@@ -43,13 +43,10 @@ impl psyche_tui::CustomWidget for CoordinatorTui {
             let vsplit = Layout::vertical(Constraint::from_fills([1, 1])).split(coord_split[1]);
             {
                 Paragraph::new(
-                    [
-                        format!("Data Source: {}", state.data_source),
-                        format!("Model Checkpoint: {}", state.model_checkpoint),
-                    ]
-                    .into_iter()
-                    .map(Line::from)
-                    .collect::<Vec<_>>(),
+                    [format!("Model Checkpoint: {}", state.model_checkpoint)]
+                        .into_iter()
+                        .map(Line::from)
+                        .collect::<Vec<_>>(),
                 )
                 .block(Block::bordered().title("Config"))
                 .render(vsplit[0], buf);
@@ -169,7 +166,6 @@ pub struct CoordinatorTuiState {
     pub run_state: TuiRunState,
     pub height: u32,
     pub clients: Vec<String>,
-    pub data_source: String,
     pub model_checkpoint: String,
     pub exited_clients: usize,
     pub pending_pause: bool,
@@ -187,9 +183,6 @@ impl<T: NodeIdentity> From<&Coordinator<T>> for CoordinatorTuiState {
                 .iter()
                 .map(|c| format!("{:?}", c.id))
                 .collect(),
-            data_source: match &value.model {
-                Model::LLM(l) => format!("{:?}", l.data_type),
-            },
             model_checkpoint: match &value.model {
                 Model::LLM(l) => format!("{}", l.checkpoint),
             },
diff --git a/tools/rust-tools/preview-lr/src/main.rs b/tools/rust-tools/preview-lr/src/main.rs
index ffea7ea00..51c52a3c6 100644
--- a/tools/rust-tools/preview-lr/src/main.rs
+++ b/tools/rust-tools/preview-lr/src/main.rs
@@ -1,6 +1,6 @@
 use clap::Parser;
 use plotters::prelude::*;
-use psyche_coordinator::{CoordinatorConfig, model::Model};
+use psyche_coordinator::{CoordinatorConfig, model_extra_data::ModelExtraData};
 use serde::Deserialize;
 use std::path::PathBuf;
 
@@ -28,7 +28,7 @@ enum Commands {
 #[derive(Deserialize)]
 struct Config {
     pub config: CoordinatorConfig,
-    pub model: Model,
+    pub model_extra_data: ModelExtraData,
 }
 fn main() -> anyhow::Result<()> {
     let args = Args::parse();
@@ -48,9 +48,8 @@ fn main() -> anyhow::Result<()> {
 
     let config: Config = toml::from_str(&std::fs::read_to_string(&config_path)?)?;
 
-    let Model::LLM(llm) = config.model;
     let steps = config.config.total_steps;
-    let lr = llm.lr_schedule;
+    let lr = config.model_extra_data.lr_schedule;
 
     let root = BitMapBackend::new("lr-plot.png", (steps.min(10_000), 1024)).into_drawing_area();
     root.fill(&WHITE)?;
diff --git a/tools/rust-tools/run-manager/Cargo.toml b/tools/rust-tools/run-manager/Cargo.toml
index e47a1931f..c6782c9e1 100644
--- a/tools/rust-tools/run-manager/Cargo.toml
+++ b/tools/rust-tools/run-manager/Cargo.toml
@@ -22,6 +22,7 @@ psyche-solana-authorizer.workspace = true
 psyche-solana-treasurer.workspace = true
 psyche-coordinator.workspace = true
 psyche-core.workspace = true
+psyche-data-provider.workspace = true
 anchor-client.workspace = true
 anchor-lang.workspace = true
 anchor-spl.workspace = true
diff --git a/tools/rust-tools/run-manager/src/commands/run/update_config.rs b/tools/rust-tools/run-manager/src/commands/run/update_config.rs
index 641577307..7356de704 100644
--- a/tools/rust-tools/run-manager/src/commands/run/update_config.rs
+++ b/tools/rust-tools/run-manager/src/commands/run/update_config.rs
@@ -7,9 +7,12 @@ use clap::Args;
 use psyche_coordinator::{
     CoordinatorConfig, CoordinatorProgress, get_data_index_for_step,
     model::{Checkpoint, Model},
+    model_extra_data::{CONFIG_PREFIX, MODEL_CONFIG_FILENAME, ModelExtraData},
 };
+use psyche_data_provider::upload_json_to_gcs;
 use psyche_solana_treasurer::logic::RunUpdateParams;
 use serde::{Deserialize, Serialize};
+use tracing::info;
 
 use crate::{SolanaBackend, instructions};
 
@@ -40,6 +43,12 @@ pub struct CommandUpdateConfig {
     // end metadata
     #[clap(long, env)]
     pub client_version: Option<String>,
+    #[clap(long, default_value_t = false, hide = true)]
+    pub skip_upload_model_extra_data: bool,
+
+    /// HuggingFace token for uploading to Hub repos (can also use HF_TOKEN env var)
+    #[clap(long, env = "HF_TOKEN")]
+    pub hub_token: Option<String>,
 }
 
 #[async_trait]
@@ -56,6 +65,8 @@ impl Command for CommandUpdateConfig {
             num_parameters,
             vocab_size,
             client_version,
+            skip_upload_model_extra_data,
+            hub_token,
         } = self;
 
         let main_authority = backend.get_payer();
@@ -69,12 +80,13 @@ impl Command for CommandUpdateConfig {
             .get_coordinator_account(&coordinator_account)
             .await?;
 
-        let (config, mut model) = match config_path {
+        let (config, mut model, model_extra_data) = match config_path {
             Some(config_path) => {
                 #[derive(Serialize, Deserialize)]
                 struct State {
                     pub config: CoordinatorConfig,
                     pub model: Model,
+                    pub model_extra_data: ModelExtraData,
                 }
                 let state: State = toml::from_str(std::str::from_utf8(
                     &std::fs::read(&config_path).with_context(|| {
@@ -83,9 +95,13 @@ impl Command for CommandUpdateConfig {
                 )?)
                 .with_context(|| format!("failed to parse config toml file {config_path:?}"))?;
 
-                (Some(state.config), Some(state.model))
+                (
+                    Some(state.config),
+                    Some(state.model),
+                    Some(state.model_extra_data),
+                )
             }
-            None => (None, None),
+            None => (None, None, None),
         };
 
         model = if switch_to_hub {
@@ -135,6 +151,53 @@ impl Command for CommandUpdateConfig {
             coordinator_account_state.state.coordinator.model = model;
         }
 
+        // Upload model extra data to GCS or hub repo depending of the model checkpoint
+        if !skip_upload_model_extra_data {
+            if let Some(model_extra_data) = model_extra_data {
+                let Model::LLM(llm) = &coordinator_account_state.state.coordinator.model;
+                match llm.checkpoint {
+                    Checkpoint::Gcs(ref gcs_repo) | Checkpoint::P2PGcs(ref gcs_repo) => {
+                        let bucket = gcs_repo.bucket.to_string();
+                        let path = format!("{}/{}", CONFIG_PREFIX, MODEL_CONFIG_FILENAME);
+                        info!("Uploading model extra data to gs://{}/{}", bucket, path);
+                        upload_json_to_gcs(&bucket, &path, &model_extra_data)
+                            .await
+                            .with_context(|| {
+                                format!(
+                                    "failed to upload model extra data to gs://{}/{}",
+                                    bucket, path
+                                )
+                            })?;
+                        println!("Uploaded model extra data to gs://{}/{}", bucket, path);
+                    }
+                    Checkpoint::Hub(ref hub_repo) | Checkpoint::P2P(ref hub_repo) => {
+                        let repo_id = hub_repo.repo_id.to_string();
+                        let path = format!("{}/{}", CONFIG_PREFIX, MODEL_CONFIG_FILENAME);
+                        psyche_data_provider::upload_model_extra_data_to_hub(
+                            &repo_id,
+                            &path,
+                            &model_extra_data,
+                            hub_token.clone(),
+                            None,
+                        )
+                        .await
+                        .with_context(|| {
+                            format!(
+                                "failed to upload model extra data to Hub repo {}/{}",
+                                repo_id, path
+                            )
+                        })?;
+                        println!("Uploaded model extra data to Hub repo {}/{}", repo_id, path);
+                    }
+                    _ => {
+                        println!(
+                            "Warning: model_extra_data provided but checkpoint is not GCS- or Hub-based, skipping upload"
+                        );
+                    }
+                }
+            }
+        }
+
         let progress = restart_from_step.map(|step| CoordinatorProgress {
             epoch: coordinator_account_state.state.coordinator.progress.epoch,
             step,
diff --git a/website/backend/src/dataStores/flatFileCoordinator.ts b/website/backend/src/dataStores/flatFileCoordinator.ts
index 6bdc15bba..d2438530e 100644
--- a/website/backend/src/dataStores/flatFileCoordinator.ts
+++ b/website/backend/src/dataStores/flatFileCoordinator.ts
@@ -4,7 +4,6 @@ import {
 	Model,
 	PsycheCoordinator,
 	RunMetadata,
-	lr_at_step,
 } from 'psyche-deserialize-zerocopy-wasm'
 import {
 	RunSummary,
@@ -291,14 +290,6 @@ export class FlatFileCoordinatorDataStore implements CoordinatorDataStore {
 		lastRun.lastUpdated = eventTime
 		lastRun.lastState = newState
 
-		const step = newState.coordinator.progress.step
-		if (step > (lastRun.observedLrByStep.at(-1)?.[0] ?? 0)) {
-			const lr = lr_at_step(newState.coordinator.model.LLM.lr_schedule, step)
-			if (isGoodNumber(lr)) {
-				lastRun.observedLrByStep.push([step, lr])
-			}
-		}
-
 		if (configChanged) {
 			lastRun.configChanges.push({
 				timestamp: eventTime,
@@ -673,8 +664,6 @@ export class FlatFileCoordinatorDataStore implements CoordinatorDataStore {
 					maxRoundTrainTime: Number(config.max_round_train_time),
 					roundWitnessTime: Number(config.round_witness_time),
 					warmupTime: Number(config.warmup_time),
-
-					lrSchedule: c.coordinator.model.LLM.lr_schedule,
 				},
 			}
 		}
@@ -746,7 +735,6 @@ function makeRunSummary(
 		: undefined
 
 	const summary: RunSummary = {
-		arch: c.model.LLM.architecture,
 		id: c.run_id,
 		index: index,
 		isOnlyRunAtThisIndex,
diff --git a/website/frontend/src/components/RunSummary.tsx b/website/frontend/src/components/RunSummary.tsx
index 57a9af6e2..d72e69a44 100644
--- a/website/frontend/src/components/RunSummary.tsx
+++ b/website/frontend/src/components/RunSummary.tsx
@@ -55,7 +55,6 @@ const InfoChits = styled.div`
 export const RunSummaryCard = memo(function RunSummaryCard({
 	info: {
 		id,
-		arch,
 		description,
 		name,
 		size,
@@ -93,7 +92,6 @@ export const RunSummaryCard = memo(function RunSummaryCard({
 				{size !== 0n && (
 					<InfoChit label="params">{formatNumber(Number(size), 2)}</InfoChit>
 				)}
-				<InfoChit label="arch">{arch}</InfoChit>
 				<InfoChit label="type">{type}</InfoChit>
 				<InfoChit label="tokens">
 					{formatNumber(Number(totalTokens), 2)}
diff --git a/website/frontend/src/fakeData.ts b/website/frontend/src/fakeData.ts
index eb3d062b5..37a7ce0b1 100644
--- a/website/frontend/src/fakeData.ts
+++ b/website/frontend/src/fakeData.ts
@@ -60,7 +60,6 @@ export const fakeRunSummaries: RunSummary[] = [
 		status: { type: 'paused' },
 		totalTokens: 100000n,
 		size: 1000000000n,
-		arch: 'HfLlama',
 		type: 'vision',
 		pauseHistory: [],
 		lastUpdate: {
@@ -77,7 +76,6 @@ export const fakeRunSummaries: RunSummary[] = [
 		status: { type: 'active' },
 		totalTokens: 200000n,
 		size: 2000000000n,
-		arch: 'HfLlama',
 		type: 'text',
 		pauseHistory: [],
 		lastUpdate: {
@@ -100,7 +98,6 @@ export const fakeRunSummaries: RunSummary[] = [
 		}, // 1 day ago
 		totalTokens: 50000n,
 		size: 500000000n,
-		arch: 'HfLlama',
 		type: 'text',
 		pauseHistory: [],
 		lastUpdate: {
@@ -117,7 +114,6 @@ export const fakeRunSummaries: RunSummary[] = [
 		status: { type: 'active' },
 		totalTokens: 100000n,
 		size: 1000000000n,
-		arch: 'HfLlama',
 		type: 'vision',
 		pauseHistory: [],
 		lastUpdate: {
@@ -394,15 +390,6 @@ function makeFakeRunDataSeeded(seed = 1, step = 0, index = 0): RunData {
 				roundWitnessTime: 2_000,
 				minClients,
 				epochTime,
-				lrSchedule: {
-					Cosine: {
-						base_lr: 4.0e-4,
-						warmup_steps: 500,
-						warmup_init_lr: 0.0,
-						total_steps: 25000,
-						final_lr: 4.0e-5,
-					},
-				},
 			},
 		},
 	}
diff --git a/website/frontend/src/routes/runs/$run.$index.tsx b/website/frontend/src/routes/runs/$run.$index.tsx
index 943f2abf4..ebb6625cc 100644
--- a/website/frontend/src/routes/runs/$run.$index.tsx
+++ b/website/frontend/src/routes/runs/$run.$index.tsx
@@ -178,7 +178,6 @@ function RouteComponent() {
 									<InfoChit label="params">
 										{formatNumber(Number(info.size), 2)}
 									</InfoChit>
-									<InfoChit label="arch">{info.arch}</InfoChit>
 									<InfoChit label="type">{info.type}</InfoChit>
 								</InfoChits>
 
diff --git a/website/shared/index.ts b/website/shared/index.ts
index 0b19b75d0..b415443ef 100644
--- a/website/shared/index.ts
+++ b/website/shared/index.ts
@@ -11,8 +11,6 @@ type PsycheSolanaMiningPool = miningPoolTypes.PsycheSolanaMiningPool
 import type {
 	GcsRepo,
 	HubRepo,
-	LearningRateSchedule,
-	LLMArchitecture,
 	RunState,
 } from 'psyche-deserialize-zerocopy-wasm'
 
@@ -73,7 +71,6 @@ export interface RunSummary {
 	}
 
 	size: bigint
-	arch: LLMArchitecture
 	type: ModelType
 }
 
@@ -131,8 +128,6 @@ export interface RunData {
 
 			maxRoundTrainTime: number
 			roundWitnessTime: number
-
-			lrSchedule: LearningRateSchedule
 		}
 	}
 	recentTxs: Array<TxSummary>
diff --git a/website/wasm/Cargo.toml b/website/wasm/Cargo.toml
index 54c58a6c2..c9ff68400 100644
--- a/website/wasm/Cargo.toml
+++ b/website/wasm/Cargo.toml
@@ -8,6 +8,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 psyche-solana-coordinator = { path = "../../architectures/decentralized/solana-coordinator/programs/solana-coordinator" }
+psyche-coordinator.workspace = true
 serde.workspace = true
 serde-wasm-bindgen = "0.6.5"
 wasm-bindgen = "=0.2.108"
diff --git a/website/wasm/src/lib.rs b/website/wasm/src/lib.rs
index 1beee51dd..f57cf73da 100644
--- a/website/wasm/src/lib.rs
+++ b/website/wasm/src/lib.rs
@@ -1,3 +1,4 @@
+use psyche_coordinator::model::LLMArchitecture;
 use psyche_core::LearningRateSchedule;
 use psyche_solana_coordinator::{ClientId, CoordinatorAccount, coordinator_account_from_bytes};
 use serde::ser::Serialize;
@@ -38,3 +39,14 @@ pub struct DummyCoordinatorAccount(CoordinatorAccount);
 #[derive(TS)]
 #[ts(export)]
 pub struct DummyClientId(ClientId);
+
+// Export types that are now in ModelExtraData but still needed by the website
+#[allow(dead_code)]
+#[derive(TS)]
+#[ts(export)]
+pub struct DummyLLMArchitecture(LLMArchitecture);
+
+#[allow(dead_code)]
+#[derive(TS)]
+#[ts(export)]
+pub struct DummyLearningRateSchedule(LearningRateSchedule);