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

Annotations mark this destructive and non-idempotent, and the description adds genuinely new behavior: the replaced film is preserved as its own version, making the operation reversible via undo_film. That reversibility detail is exactly the context annotations cannot express; only the lack of any permission or side-effect detail on the replaced film's id keeps it from 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 compact sentences, no filler, with the reversibility fact front-loaded alongside the action rather than buried. Every clause carries information an agent needs.

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 two-parameter mutation with full schema coverage and no output schema, the description covers the key risk (reversibility) and the version source. It stops short of stating what the call returns or whether the film id must match the version's owner, but 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 coverage is 100%, and the schema already documents both parameters including the prj_ prefix and the timestamp-style version id. The description's '(an id from list_versions)' largely restates the schema's own note, so 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 ('Put an earlier version of a film back') and immediately clarifies the version argument's origin via list_versions. This distinguishes it from sibling restore_film (deleted films) and edit_film in a single readable sentence.

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?

Names the prerequisite tool (list_versions) and the escape hatch ('undo_film cancels the restore'), which tells the agent when this is safe to invoke. It does not explicitly contrast with restore_film, so the agent must infer that distinction from the names.

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