read_mail

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

Beyond the readOnly/openWorld annotations, the description adds genuinely useful behavioral detail: hidden HTML text is stripped, sender-authenticity warnings are surfaced, and the content is flagged as untrusted. That last point is an important safety signal for downstream handling, though nothing is said about large-message truncation behavior.

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 dense sentences with no filler, front-loading the operation and then the return contents. The parenthetical about hidden HTML is the kind of qualifier that earns its place.

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 annotations covering the safety profile and an output schema covering return structure, the description is nearly complete for a simple read tool. The one gap is routing guidance against get_thread and search_mail, which would help an agent choose correctly.

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 coverage is 100%, so id, max_chars, and strip_quotes are already fully documented in the schema. The description adds no additional parameter meaning (for example, how truncation interacts with max_chars), so the baseline of 3 applies.

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?

A specific verb and resource ('Read one message') followed by the exact contents returned: headers, sender-authenticity warnings, attachment list, and reader-visible text. The 'one message' framing implicitly contrasts with get_thread, but no sibling is named, so the differentiation is left to inference.

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 single-message scope implies when this applies versus a thread reader, but there is no explicit when-to-use or when-not-to-use statement and no pointer to search_mail or get_thread as alternatives. Usage is inferable rather than stated.

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