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 thoroughly. It discloses that the text becomes a requester-readable comment, is emailed, requires full write access, and reports email success/failure with 'emailed' or 'emailError', including the note that the reply is kept either way.

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 compact and every sentence earns its place: purpose, distinction from sibling, language guidance, permission requirement, and return behavior. The key behavioral contrast is front-loaded in the first sentence.

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 two-parameter tool with no annotations and no output schema, the description fully covers what an agent needs: what to write, how it is delivered, permissions, language handling, and the response shape including failure behavior.

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 both key and body fully. The description adds context about the body becoming a visible comment, but it does not add new parameter-level semantics beyond what the schema provides. Baseline 3 is appropriate.

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 names a specific verb and resource: 'Write to the person who opened a support request.' It clearly distinguishes this from add_comment by explaining that replies are visible to and emailed to the requester, while add_comment is internal only.

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 explicitly contrasts reply_to_requester with add_comment, telling agents when to use this tool instead of the sibling: when the customer must see and receive the message. It also adds the language instruction and the write-access prerequisite, leaving no ambiguity about appropriate use.

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