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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new context: the action is state-changing and requires authorization first, and it scopes the mutation to the filename only — consistent with the non-destructive hint. It does not cover failure modes such as filename collisions or reversibility, which 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 sentences, front-loaded with the usage trigger followed by the behavioral note. Nothing is wasted, though "this state-changing action updates the filename" is mildly redundant phrasing for what is simply a rename.

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 rename with full schema coverage and no output schema, the description supplies what an agent needs: the trigger, the authorization prerequisite, and the exact field being changed. It omits any note on error or conflict behavior, which is the only real gap.

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%, so both parameters (generation_id, filename) are already fully documented in the schema, including the 255-character limit and the instruction to call list-generations first. The description adds no format, validation, or constraint detail beyond that, 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 description states a specific verb+resource: it renames an existing generated result by updating the filename for a generation_id. That cleanly separates it from get-generation, archive-generation, restore-generation, and set-generation-definitive-version. It stops short of explicitly naming a sibling to contrast against, so it lands at a solid 4 rather than 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?

"Use this when the user wants to rename an existing generated result" gives an explicit triggering condition, which is more than implied usage. It provides no when-not guidance (e.g., use archive-generation to retire a result) and no mention of alternatives among the many sibling generation tools, so it is clear context without exclusions.

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