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

Annotations already indicate readOnlyHint=false (mutation) and destructiveHint=false (no destruction). The description adds the partial-update behavior ('Only fields you pass are changed; omitted fields are preserved'), which is useful. However, it does not discuss side effects, idempotency, or permission requirements, so it adds moderate but not deep behavioral context beyond the annotations.

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?

The description is concise, with two short paragraphs. The first sentence immediately states purpose. The rest efficiently explains how to get the id, the partial-update nature, and the deletion alternative. No unnecessary words or repetition.

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?

Given the tool has 10 parameters, no output schema, and no nested objects, the description covers essential context: how to obtain the id (via get_project), that updates are partial, and the alternative for deletion. It does not explain error handling or validation, but for a mutable tool with good sibling references and schema, it is fairly 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 100% – all 10 parameters have individual descriptions in the input schema. The description lists a few examples (volume, fades, timing, loop) but adds no new semantic meaning beyond what the schema already provides. The baseline of 3 is appropriate since the schema does the heavy lifting.

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 clearly states the tool's purpose: 'Mutate fields on an existing music/SFX track by id.' It uses a specific verb ('mutate') and resource ('audio track'), and the mention of flipping knobs like volume, fades, timing, loop distinguishes it from sibling tools like add_audio (adding new tracks) and remove_from_project (deleting tracks).

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 description provides explicit guidance: read existing tracks via get_project.audio_tracks to get the id and current shape, then use this tool to update specific fields. It also clearly directs to use remove_from_project(target='audio') for deletion, a key alternative. It does not explicitly mention when to use add_audio instead, but the context is strong enough for an agent to differentiate.

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