Reply To Thread

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

Annotations already declare idempotentHint=true and destructiveHint=false, so the description adds little beyond that. It does not mention side effects like whether the reply is sent immediately or queued, nor any permissions needed.

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, both essential: first states purpose, second provides critical usage constraint. No wasted words, front-loaded with key information.

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?

With an output schema present but unseen, the description fails to indicate what the reply returns (e.g., success message, updated thread). Low schema coverage and missing param details leave significant gaps for a mutation tool.

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 low at 29%, but the tool description adds no information about parameters beyond what exists in the schema. Parameters like 'to', 'cc', 'html' have no descriptions in schema, and the description does not clarify them.

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 'Reply to a thread' which identifies the verb and resource. It distinguishes from siblings like 'send_message' (new thread) and 'reply_to_message' (reply to specific message) but could be more explicit about the difference.

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 includes 'Use only after the user approves the exact recipients and content' which explicitly tells the agent when to invoke this tool. It implies not to use without approval, but does not list when-not-to-use or alternative tools.

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