Add flow blockchain with CAIP-2

flow/README.md

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+---
+namespace-identifier: flow
+title: Flow Namespace
+author: Hao Fu
+status: Draft
+type: Informational
+created: 2026-01-13
+requires: ["CAIP-2"]
+---
+
+# Namespace for Flow
+
+Flow is a layer-1 blockchain focused on scalable smart contracts and consumer applications.
+This namespace documents how Flow networks are identified for CAIP use cases.
+
+## Rationale
+
+Flow networks are distinguished by stable, human-readable network names.
+A clear CAIP-2 profile makes these networks unambiguous across wallets, dapps, and tooling.
+
+## Governance
+
+Flow protocol changes are governed by the Flow community and its core development process.
+Network identifiers in this namespace are expected to remain stable for each network.
+
+## References
+
+- [Flow] - Official Flow website and documentation portal.
+- [Flow Developers] - Flow developer documentation.
+- [Flow GitHub] - Flow open source repositories.
+- [CAIP-2] - Chain ID Specification.
+
+[Flow]: https://flow.com
+[Flow Developers]: https://developers.flow.com/
+[Flow GitHub]: https://github.com/onflow
+[CAIP-2]: https://chainagnostic.org/CAIPs/caip-2
+
+## Copyright
+
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).

flow/caip2.md

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+---
+namespace-identifier: flow-caip2
+title: Flow Namespace - Chains
+author: Hao Fu
+discussions-to: https://github.com/ChainAgnostic/namespaces/issues/163
+status: Draft
+type: Informational
+created: 2026-01-13
+requires: CAIP-2
+---
+
+# CAIP-2
+
+_For context, see the [CAIP-2][] specification._
+
+## Introduction
+
+The Flow namespace uses short, human-readable network identifiers.
+These identifiers are stable and map to distinct Flow networks.
+
+## Specification
+
+### Semantics
+
+A valid Flow CAIP-2 identifier takes the form:
+
+`flow:<network>`
+
+Where `<network>` is one of the following reserved identifiers:
+
+- `mainnet`
+- `testnet`
+
+### Syntax
+
+#### Regular Expression
+
+`^flow:(mainnet|testnet)$`
+
+#### Example
+
+`flow:mainnet`
+
+### Resolution Mechanics
+
+Clients should resolve a Flow network identifier by querying the Flow REST API network parameters endpoint for the target network and verifying the returned `chain_id`.
+
+**Sample request (mainnet):**
+
+`GET https://rest-mainnet.onflow.org/v1/network/parameters`
+
+**Sample response:**
+
+```json
+{
+  "chain_id": "flow-mainnet"
+}
+```
+
+## Rationale
+
+Stable, human-readable network names provide a simple and consistent way to identify Flow networks across tooling.
+
+### Backwards Compatibility
+
+There are no legacy identifiers for Flow networks in this namespace.
+
+## Test Cases
+
+- **Flow Mainnet:** `flow:mainnet`
+- **Flow Testnet:** `flow:testnet`
+
+## References
+
+- [Flow] - Official Flow website and documentation portal.
+- [CAIP-2] - Chain ID Specification.
+
+[Flow]: https://flow.com
+[CAIP-2]: https://chainagnostic.org/CAIPs/caip-2
+
+## Copyright
+
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).