message-respond

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

With no annotations, the description carries the full burden of disclosing behavior. It indicates a side effect (sending) but does not clarify whether recipients/subject are derived automatically, what happens to the original message, or whether auth/permissions are required.

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 a single concise sentence with no filler, and the core action is front-loaded. It earns its place entirely.

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?

The schema fully covers parameters and an output schema exists, but the description lacks annotations and adds no behavioral or usage context. For a simple one-action tool this is adequate but leaves nontrivial gaps around selection and side effects.

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 baseline is 3. The tool description itself adds no parameter-level meaning, but the schema already documents id, body, and contentType, including the enum and default for contentType.

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 action ('Send a reply') and resource ('a Gmail message'), making the basic purpose clear. It does not explicitly contrast with sibling tools like message-send, though the word 'reply' differentiates it by implication.

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 guidance is given on when to use this tool versus message-send or whether the caller must first fetch the message to obtain an ID. Usage is only implied by the tool name and one-sentence description.

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