Runway MCP bills credits, no API key; Sume's hosted MCP uses scopes

Runway's MCP needs no API key: you sign in with your Runway account, and generations draw credits just like the web app, with no Explore Mode. Sume's hosted MCP signs in by OAuth, which defaults to read-only mcp:read; paid and write tools need mcp:write, or an API key session. There is no mcp:paid scope, so spend is controlled by the wallet and by per-call gates.

Auth and spend

What read-only means in practice

With only mcp:read, tools such as jobs_list and catalog_list work, while generate_image and avatars_create return insufficient_scope. That default is a useful trial mode: you can check the connection and the tool contract before any money is at risk.

Preview a paid call

Read the contract first with tools_schema, then preview. dry_run=true returns an admission and cost preview without submitting the job. max_spend_usd is enforced only when provided, so send it on paid calls an agent makes unattended.

Call tools_schema with name "generate_video". Explain idempotency_key,
dry_run and max_spend_usd. Then call generate_video with dry_run=true
and report the preview. Do not submit the job.

Choose the default

• Exploring from a chat with a Runway plan: Runway's connector keeps everything in one credit balance.
• An agent that may spend a dollar wallet: start read-only, add Write on purpose, and pass max_spend_usd on every paid call.