Runway MCP workflows vs Sume hosted MCP tool chains

Runway's changelog says workflow support in Runway MCP lets agents list the workflows in your workspace, open one in the web editor, tweak it and run it from chat. Sume's hosted MCP works at a lower level: it exposes single tools, and you chain them yourself, for example timeline_compose, then jobs_wait, then jobs_result. Paid and write calls need an idempotency_key.

Runway's entry is a short changelog note. Sume details are from Hosted MCP, Timeline compose and Timeline audio, read 2026-10-01.

What did Runway add?

The entry describes workflows as built for advanced, re-runnable pipelines you do not want to assemble by hand. The saved pipeline lives in the product; chat lists it, opens it and runs it.

What does the Sume chain look like?

The docs give two flows. For a shot: timeline_compose, jobs_wait, jobs_result, then drop the returned video_url into timeline_create video[]. For audio: timeline_audio, jobs_wait, jobs_result.

Who controls spending?

With OAuth, mcp:read sees read-only tools; paid and mutating tools appear only if you opt in to mcp:write. There is no mcp:paid scope. With an API key you get the full hosted tool set, and the wallet and admission rules are the spend gate.

How do I make a chain re-runnable?

Keep the steps in your agent's instructions, and give each write call a stable idempotency_key so a repeated tool call does not pay twice. Details on that failure are in a tool call that ran twice, and the wait step is explained in MCP jobs_wait for long video jobs.