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

No annotations are provided, so the description carries the full burden. It states the tool reads content, implying a read-only operation, but doesn't disclose behavioral traits such as authentication needs, rate limits, error conditions, or what 'full content' includes beyond body text (e.g., headers, attachments). For a tool with no annotations, this leaves significant gaps in transparency.

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, efficient sentence that front-loads the core purpose ('Read the full content of a specific email message') and adds a clarifying detail ('including the body text'). There is no wasted language, and it's appropriately sized for the tool's complexity.

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 no annotations, no output schema, and a read operation with two parameters, the description is incomplete. It doesn't explain return values (e.g., format of the content), error handling, or dependencies like needing message_id from check_inbox. For a tool that retrieves data, more context is needed to guide effective use.

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 parameters (message_id and address) with clear descriptions. The description doesn't add any meaning beyond what the schema provides, such as explaining parameter interactions or constraints. Baseline 3 is appropriate when the schema does the heavy lifting.

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 action ('Read') and resource ('full content of a specific email message'), including the scope ('including the body text'). It distinguishes from check_inbox (which lists messages) but doesn't explicitly differentiate from other siblings like send_email. The purpose is specific but lacks explicit sibling differentiation for a perfect score.

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 when needing detailed message content, as opposed to check_inbox for listing messages. However, it doesn't explicitly state when to use this tool versus alternatives or mention prerequisites like requiring a valid message_id from check_inbox. Usage is contextually implied but not clearly articulated.

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