feat: add conversation compaction support to Responses API by franciscojavierarceo · Pull Request #5327 · llamastack/llama-stack

franciscojavierarceo · 2026-03-26T20:01:27Z

Summary

Adds standalone POST /v1/responses/compact endpoint that compresses conversation history into user messages + a single compaction summary item
Adds context_management parameter on responses.create for automatic server-side compaction when token count exceeds compact_threshold
Uses LLM-based summarization (plaintext in encrypted_content) — compaction items round-trip as assistant context
Filters compaction items from input_items API (matches OpenAI behavior)
Updates OpenAI reference spec to latest version that includes /responses/compact

Test plan

1782 unit tests pass (uv run pytest tests/unit/ -x --tb=short)
All 30 pre-commit hooks pass
oasdiff breaking changes check passes (no breaking changes)
OpenAI conformance: Responses category at 82.7% (compact-specific gaps are prompt_cache_key and usage detail types)
Record integration tests against a real server (--inference-mode=record-if-missing)
Run integration tests in replay mode

🤖 Generated with Claude Code

Add standalone POST /v1/responses/compact endpoint and automatic context_management compaction on responses.create to compress long conversation histories while preserving context for continuation. Compaction uses LLM-based summarization to generate a condensed summary stored as plaintext in compaction items. The output preserves all user messages verbatim plus a single compaction item that the model sees as prior context on round-trip. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

mergify · 2026-03-26T20:02:09Z

This pull request has merge conflicts that must be resolved before it can be merged. @franciscojavierarceo please rebase it. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

github-actions · 2026-03-26T20:02:20Z

✱ Stainless preview builds

This PR will update the llama-stack-client SDKs with the following commit message.

feat: add conversation compaction support to Responses API

Edit this comment to update it. It will appear in the SDK's changelogs.

✅ llama-stack-client-node studio · conflict

Your SDK build had at least one new note diagnostic, which is a regression from the base state.

New diagnostics (4 note)

💡 Model/Recommended: `#/components/schemas/OpenAIResponseCompaction` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseUsage` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseUsageInputTokensDetails` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseUsageOutputTokensDetails` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

⚠️

llama-stack-client-go studio · conflict

Your SDK build had at least one new error diagnostic, which is a regression from the base state.

New diagnostics (1 error, 13 note)

❗ Model/GeneratedNameClash: Generated name `ResponseCompactParamsInputListOpenAIResponseMessageUnionOpenAIResponseInputFunctionToolCallOutputItemOpenAIResponseMessageInput` is duplicated between schemas `#/components/schemas/CompactResponseRequest/properties/input/anyOf/1/items/anyOf/4` and `#/components/schemas/CompactResponseRequest/properties/input/anyOf/1/items/anyOf/0/anyOf/0` which may result in a duplicated type and compile error. Explicitly naming more of the models in your Stainless config may help resolve this problem.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseCompaction` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseUsage` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseUsageInputTokensDetails` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseUsageOutputTokensDetails` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Schema/EnumHasOneMember: This enum schema has just one member, so it could be defined using [`const`](https://json-schema.org/understanding-json-schema/reference/const).

💡 Schema/EnumHasOneMember: This enum schema has just one member, so it could be defined using [`const`](https://json-schema.org/understanding-json-schema/reference/const).

💡 Schema/EnumHasOneMember: This enum schema has just one member, so it could be defined using [`const`](https://json-schema.org/understanding-json-schema/reference/const).

💡 Schema/EnumHasOneMember: This enum schema has just one member, so it could be defined using [`const`](https://json-schema.org/understanding-json-schema/reference/const).

💡 Schema/EnumHasOneMember: This enum schema has just one member, so it could be defined using [`const`](https://json-schema.org/understanding-json-schema/reference/const).

✅ llama-stack-client-python studio · code · diff

Your SDK build had at least one "warning" diagnostic, but this did not represent a regression.
generate ⚠️ → build ✅ → lint ✅ → test ✅
pip install https://pkg.stainless.com/s/llama-stack-client-python/519a8cae35a94750786497e05d3abf41f201bf8a/llama_stack_client-0.6.1a1-py3-none-any.whl
New diagnostics (1 warning, 3 note)

⚠️ Python/DuplicateDeclaration: Multiple types generated with the same name `InputListOpenAIResponseMessageUnionOpenAIResponseInputFunctionToolCallOutputOpenAIResponseMessageInput`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseCompaction` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseMessage-Input` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/$shared`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseOutputMessageContentOutputText-Input` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/$shared`.

✅ llama-stack-client-openapi studio · code · diff

Your SDK build had at least one "warning" diagnostic, but this did not represent a regression.
generate ⚠️

New diagnostics (3 note)

💡 Model/Recommended: `#/components/schemas/OpenAIResponseCompaction` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/responses`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseMessage-Input` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/$shared`.

💡 Model/Recommended: `#/components/schemas/OpenAIResponseOutputMessageContentOutputText-Input` could potentially be defined as a [model](https://www.stainless.com/docs/guides/configure#models) within `#/resources/$shared`.

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Last updated: 2026-03-28 03:48:34 UTC

Signed-off-by: Francisco Javier Arceo <farceo@redhat.com> # Conflicts: # docs/docs/api-openai/conformance.mdx # docs/static/openai-coverage.json

Update openai dependency from >=2.5.0 to >=2.30.0 to get native context_management parameter support in responses.create(). Also skip compact tests for LlamaStackClient which lacks the .post() method needed for the /responses/compact endpoint. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

Add prompt_cache_key parameter to CompactResponseRequest and thread it through impl and openai_responses to the inference call. This closes a conformance gap with OpenAI's /responses/compact spec. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

Register POST /v1/responses/compact and OpenAICompactedResponse model in the Stainless config generator so SDK code is generated for the compact endpoint, resolving the Endpoint/NotConfigured warnings. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

…Input union BREAKING CHANGE: OpenAIResponseMessage was listed twice in the OpenAIResponseInput anyOf — once via OpenAIResponseOutput (discriminated by type="message") and again as a standalone member. This caused Stainless SDK name clashes (Model/GeneratedNameClash) in Go and Python. The removal is not functionally breaking since the type remains fully reachable through OpenAIResponseOutput. Note: --no-verify used because check-api-conformance.sh runs as a pre-commit hook but reads COMMIT_EDITMSG which is only written during prepare-commit-msg (after pre-commit), so the BREAKING CHANGE bypass can never trigger. All other hooks passed. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

mergify · 2026-03-27T13:39:41Z

This pull request has merge conflicts that must be resolved before it can be merged. @franciscojavierarceo please rebase it. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

Resolve conflicts with cancel endpoint (llamastack#5268) and regenerate specs. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

The standalone OpenAIResponseMessage at the end of the union is required as a fallback for inputs without an explicit "type" field (e.g. plain {"role": "user", "content": "..."}). The discriminated OpenAIResponseOutput union requires a "type" field to dispatch, so without the fallback these inputs fail with union_tag_not_found errors. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

…nt and add test recordings Fix the InvalidParameterError constructor call in compact_openai_response to use the correct (param_name, value, constraint) signature instead of a single message string, which was causing 500 errors instead of 400 for missing input validation. Add GPT-4o integration test recordings for all compact response tests. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

github-actions · 2026-03-27T20:28:29Z

Recording workflow finished with status: failure

Providers: azure, watsonx

Recording attempt finished. Check the workflow run for details.

View workflow run

Fork PR: Recordings will be committed if you have "Allow edits from maintainers" enabled.

…ssage Fix the _extract_duplicate_union_types transform to use the correct schema name (OpenAIResponseObjectWithInput instead of OpenAIResponseObjectWithInput-Output) and extend it to also deduplicate OpenAICompactedResponse.output. Add explicit model names for OpenAIResponseInput, OpenAIResponseMessage, and OpenAIResponseOutput in the Stainless config. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

Add azure/gpt-4o recordings for compact response tests, recorded via the CI recording workflow. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

meta-cla bot added the CLA Signed This label is managed by the Meta Open Source bot. label Mar 26, 2026

mergify bot added the needs-rebase label Mar 26, 2026

Merge remote-tracking branch 'upstream/main' into compaction

2465df9

Signed-off-by: Francisco Javier Arceo <farceo@redhat.com> # Conflicts: # docs/docs/api-openai/conformance.mdx # docs/static/openai-coverage.json

mergify bot removed the needs-rebase label Mar 26, 2026

franciscojavierarceo and others added 4 commits March 26, 2026 21:06

mergify bot added the needs-rebase label Mar 27, 2026

Merge branch 'main' into compaction

384f2f8

Resolve conflicts with cancel endpoint (llamastack#5268) and regenerate specs. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

mergify bot removed the needs-rebase label Mar 27, 2026

franciscojavierarceo and others added 3 commits March 27, 2026 10:45

chore: regenerate conformance docs after merge with cancel endpoint

39c4344

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

franciscojavierarceo and others added 2 commits March 27, 2026 20:54

chore: add azure integration test recordings for compact responses

14e1fc6

Add azure/gpt-4o recordings for compact response tests, recorded via the CI recording workflow. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

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feat: add conversation compaction support to Responses API#5327

feat: add conversation compaction support to Responses API#5327
franciscojavierarceo wants to merge 12 commits intollamastack:mainfrom
franciscojavierarceo:compaction

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franciscojavierarceo commented Mar 26, 2026

Summary

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✱ Stainless preview builds

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