Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the mutation profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false, closed-world), so the description only needs to add context — and it does, with required scopes (demos:read, demos:write) and the practical warning that scene durations should fit the narration. It doesn't cover whether existing audio is preserved or how long generation takes, which leaves some behavioral gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences plus a scoping line — front-loaded with the action and its filter, then prerequisites. Minor density in 'Uses AI voice characters; scene durations should fit the narration (get_video shows them)' but every clause carries information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 2-parameter mutation tool with no output schema, the description covers scope, prerequisites, and one important pre-condition. What's missing is the return/latency story — whether generation is synchronous and what comes back — which an agent needs before invoking a media-generation operation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 50%: videoId is documented in the schema but sceneIds has no description. The phrase '(default: all of them)' explains exactly what omitting sceneIds does, compensating for the undocumented optional parameter. It still doesn't mention the 40-item cap or ordering, so it falls short of a 5.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Records AI narration for scenes') plus a clear scope condition ('whose script has no current audio'). It does not, however, distinguish itself from the near-identical sibling 'generate_voiceovers', so an agent comparing the two gets no disambiguating signal.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The scope rule (only scenes lacking audio, defaulting to all of them) and the pointer to get_video for checking scene durations imply when this tool is appropriate. But there is no explicit exclusion or alternative-selection guidance, which matters given the sibling generate_voiceovers looks like a direct substitute.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.