update_comment

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

The description discloses a non-obvious behavior: 'Returns previous text for rollback,' which goes beyond the annotations. Since annotations already mark it as a mutation (readOnlyHint=false) and non-destructive, the description adds useful context about the return value.

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?

The description is concise: a one-line function summary, a note about the return value, and a compact parameter list. Every sentence earns its place with no redundancy.

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 simple update tool with an output schema, the description fully covers all required inputs, the optional instance parameter, and the rollback behavior. No critical information is missing for an agent to call it correctly.

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?

The Args section explains each parameter's meaning and format, including that issue_id can be an ID or URL, text is markdown, and instance is optional. This fully compensates for the 0% schema description coverage.

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 and resource ('Update an existing comment') and adds distinguishing detail: it returns previous text for rollback. This clearly differentiates it from add_comment and delete_comment.

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: it modifies an existing comment, so it requires an existing comment ID. However, it does not explicitly state when to prefer this over alternatives or mention any exclusions, leaving the guidance implicit.

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