P1: Define SDK-facing artifact RPCs

[BunsDev]

Goal

Add SDK-facing artifact RPCs so apps like OpenMeow can render rich outputs: diffs, screenshots, logs, generated files, media, trajectories, and PR links.

Proposed methods

• artifacts.list
• artifacts.get
• artifacts.download

Acceptance criteria

• Artifacts can be queried by runId, sessionKey, or taskId.
• Artifact summaries include stable type/title/mime/size metadata.
• Download can return a URL or bytes depending on transport constraints.
• SDK can expose artifacts without apps knowing runtime internals.

References

• https://github.com/OpenCoven/open-meow-sdk/blob/main/docs/rpc-contract-proposals.md#artifactslistgetdownload
• https://github.com/OpenCoven/open-meow-sdk/blob/main/docs/prioritized-backlog.md#5-add-read-only-artifacts-rpcs

[BunsDev]

Dogfood update from 2026-05-02:

P1 SDK surface probe results:

• artifacts.list via SDK: live Gateway returned unknown method: artifacts.list.
• raw artifacts.list: live Gateway returned unknown method: artifacts.list.
• tasks.list via SDK: SDK reports this is not supported by the current Gateway yet.
• raw tasks.list: live Gateway returned unknown method: tasks.list.
• environments.list via SDK: SDK reports this is not supported by the current Gateway yet.

Assessment:

• Keep these as design/proposal issues for now.
• They are not blockers for the P0 OpenMeow chat/run/cancel dogfood path.