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

Annotations already declare readOnlyHint=false (mutation) and idempotentHint=true, which the description does not contradict. The description adds useful behavioral context: it acts only on an explicit project_id, never on the active-project pointer, and returns the project identity. This goes beyond annotations and helps the agent understand side effects and return expectations.

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 concise sentences, front-loaded with the scope constraint and then the action. No filler; every sentence earns its place. The structure is efficient and clear.

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 single-parameter tool with annotations covering safety and idempotency, the description fully covers what an agent needs: what it does, how it scopes, and where to get the id. No output schema exists, but the return behavior is mentioned ('returns the project identity'). Nothing essential is missing.

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% and the schema already describes project_id as 'Required immutable scope...'. The main description reinforces this by saying 'acts only on the explicit project_id' and 'never used to guess', but it does not add significant new meaning beyond what the schema provides. Baseline 3 applies.

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 verb (restore/undo) and resource (original mixed soundtrack), and explicitly ties it to 'undo separate_music', distinguishing it from sibling tools like remove_music or swap_music. The 'PROJECT-SCOPED' prefix further clarifies the scope.

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 gives a clear usage context: it is the inverse of separate_music, so an agent knows to call it after a stem separation. However, it does not explicitly list alternatives or when NOT to use it (e.g., vs. remove_music). The context is strong but lacks explicit exclusions.

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