reply_email

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

With no annotations provided, the description carries the full burden and does so well by disclosing key behavioral traits: automatic threading header handling, markdown body format, error responses (403 with upgrade instructions), and queuing behavior for gated oversight ('pending_approval' status). It does not cover all possible behaviors like rate limits or auth needs, but adds substantial context beyond basic functionality.

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 appropriately sized and front-loaded, starting with the core purpose and then adding critical behavioral details. Every sentence adds value, such as error handling and status warnings, with no wasted words or 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?

Given the complexity of an email reply tool with no annotations and no output schema, the description is mostly complete, covering purpose, usage context, and key behaviors. However, it lacks details on return values or success responses, which could be important for agent handling, preventing a perfect score.

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 the schema already documents all parameters. The description does not add meaning beyond the schema, such as explaining parameter interactions or constraints. Baseline 3 is appropriate as the schema handles parameter documentation adequately.

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 clearly states the specific action ('Reply to an email in its existing thread') and resource ('email'), distinguishing it from siblings like 'send_email' (new email) and 'read_email' (viewing). It specifies that threading headers are handled automatically, which adds precision.

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 provides clear context for usage by mentioning error conditions (403 error for read-only mode, 'pending_approval' for gated oversight) and advising against retries in specific cases. However, it does not explicitly compare to alternatives like 'send_email' or state when not to use it, keeping it from a perfect score.

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