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

Annotations already carry idempotentHint=true and destructiveHint=false. The description adds genuine behavioral context beyond those: the call is project-scoped, acts only on the explicit project_id, and 'returns the project identity with its result.' No contradiction with annotations, and it clarifies the return behavior which the annotations do not cover.

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?

Three tight sentences with zero filler. The scoping warning is front-loaded before the purpose, and the exclusion/alternative is last. Every sentence earns its place and the most important operational constraint appears first.

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?

There is no output schema, so the description must explain the return value; it does ('returns the project identity with its result'). Scope and the alternative tool are covered. But for a 4-parameter tool with 25% schema coverage, the missing unit semantics for start, end, and gain_db leave an agent guessing at invocation values, so it is not fully complete.

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 description coverage is only 25% (project_id alone is documented). The description partially compensates by implying start/end are SOURCE-time span boundaries and gain_db drives the volume automation, and it reinforces project_id's immutable-scope role. However, it never specifies units (seconds vs frames for start/end; whether gain_db is decibels or a multiplier), leaving the three undocumented parameters under-explained.

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?

The description uses a specific verb-resource-scope pattern: 'Volume automation on the ORIGINAL footage's audio (the speaker) over a SOURCE-time span.' It explicitly carves out the domain (speaker audio on source footage) and names what it is NOT (music/voiceover loudness), clearly distinguishing it from the sibling set_audio_gain.

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?

Provides an explicit exclusion with a named alternative: 'NOT for music or voiceover loudness — use set_audio_gain for those.' It also states the project-scoped constraint up front, telling the agent it must pass an explicit project_id. This is direct routing guidance with no inference required.

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