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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the safety profile is covered. The description adds one genuinely non-obvious behavioral fact — that success resolves to null rather than returning the updated activity — but says nothing about permissions, failure modes, or what happens if the activity does not exist.

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 short sentences, front-loaded with the action and followed by the return contract. No filler whatsoever.

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 mutation tool with two required parameters, no output schema, and only 50% parameter documentation, the description omits failure behavior, permission requirements, and any indication of whether the rename is reversible. The return-value note is the only substantive content.

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 50%: activityId has 'Numeric id' while activityName is undocumented. The description only loosely implies that activityName is the new name and activityId the target, adding essentially nothing beyond the schema and leaving the undocumented parameter unexplained.

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 ('Renames an activity'), which is unambiguous about the mutation target. It does not explicitly distinguish itself from nearby setters like set_activity_description or set_activity_type, so it falls 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?

No when-to-use guidance, no prerequisites, and no mention of alternatives among the many set_activity_* siblings. The agent must infer everything about when this is the right call.

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