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

annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds real behavioral detail beyond that: derived start times, generation status, the meaning of length_estimated=true, and the invariant that the returned asset ids are what every asset_id argument accepts. No pagination or error-missing-project behavior is described, keeping it off a 5.

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 sentences, both front-loaded: the return inventory first, the usage trigger last. The nested parenthetical explaining length_estimated is dense but earns its place by removing a real ambiguity. Nothing is wasted, though the single long sentence is heavy to parse.

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 carries the burden of describing returns, and it does so field by field, including the semantic edge case of estimated scene lengths. Missing only failure behavior for an unknown project_id and any note on result size, which for a full composition read could matter.

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?

Only one parameter, project_id, and schema coverage is 100% with a description naming the vp_… format. The description adds nothing about the parameter, so the schema does all the work and 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?

States a specific verb and resource ('Read the current composition') and then enumerates exactly what the read returns: scenes in order, tracks, clips, overlays, caption count, duration, assets. That makes the tool's output unambiguous. It does not name a sibling to distinguish itself from (e.g. studio_project_read or studio.list_versions), so it stops short of a 5.

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?

'Call when you need fresh truth after edits' gives a concrete usage trigger tied to a read-after-write workflow. It implies the read-only, non-mutating role implicitly. It states no explicit exclusions or alternatives among the many studio.* siblings, so guidance is clear but not complete.

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