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

With annotations already declaring read-only, idempotent, non-destructive behavior, the description adds substantial non-obvious context: versions are ordered most-recent-first, retention is capped at the 20 most recent, and each entry carries a timestamp, length, and shot count. The retention cap in particular is behavioral information an agent could not infer from annotations or schema.

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?

One dense sentence with front-loaded ordering and scope information, followed by return-field content. Every clause carries information, though the colon-chained structure is slightly run-on compared to a cleaner two-sentence split.

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?

No output schema exists, but the description compensates by enumerating the return fields (id, written moment, length, shot count). The 20-version cap is disclosed. It does not address pagination or behavior beyond the cap, which is a minor residual gap for a read-only list tool.

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?

There is a single parameter whose schema description is at 100% coverage, already documenting the prj_… id format and pointing to list_films. The description adds no additional parameter detail, which is acceptable given the schema does the work, so the 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 first clause names the resource and scope precisely: 'The earlier versions of a film, most recent first.' It also routes the agent to the downstream consumer (restore_version), which distinguishes it from sibling tools like get_film or undo_film.

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 implies usage (fetch version history, then pass an id to restore_version) but never explicitly says when to call this versus restore_film, undo_film, or get_film, nor does it state exclusions. The mention of restore_version is a helpful contextual hint rather than full guidance.

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