Opus 5.5 computer toolset rejects strict: Sume tools do not need it

Anthropic's strict tool use guide says the computer_toolset_20260801 and browser_toolset_20260801 entries do not accept strict: true, and a request that sets it on either is rejected. That matters little for Sume: generating video, images, speech and music through Sume is a set of API and MCP tool calls with typed inputs, not a screen you click. A Claude agent can use strict, schema-checked Sume tools and leave the clicking toolsets off, which also keeps paid actions behind explicit guardrails.

What Anthropic documents

The strict tool use guide says strict: true on a tool definition makes Claude's tool inputs match your JSON Schema, and that the computer use and browser use toolset entries do not accept it. The Claude Platform release notes add that Claude Opus 5.5 launched on 2026-09-22 and that on it tool_choice types any and tool return a 400, so Anthropic points to auto with strict tool use. So your own function tools can be strict, and the toolsets cannot.

Two ways to reach the same result

What this means in practice

The MCP tools and gates page lists the Sume tools and the gates on writes and paid calls. A paid tool needs an idempotency_key, can take dry_run, and enforces max_spend_usd when you provide it. None of that exists when an agent drives a web UI by pixels. If you point a Claude agent at the Sume web app through a computer toolset, you also give up those controls and the job ids.

So the advice is simple. Give Claude the hosted MCP server at the URL in the MCP quickstart, mark your own custom tools strict, and keep computer use for software that has no API.

• Strict, schema-checked tools for everything with an API.
• Computer use only where no API exists.
• Spend caps stated in the tool call, not hoped for.
• Read-only OAuth for exploration; add write only when you will create.