get_message

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

Annotations already provide readOnlyHint=true, so the safety profile is covered. The description adds some behavioral context beyond the annotation (default body format is plain text, full-read scope including attachments and delivery status), but does not address edge behaviors such as error handling for missing messages or session/auth requirements.

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?

A single, front-loaded sentence with zero filler. The primary verb-resource pair leads, and the content enumeration is compact yet complete.

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 read-only tool with readOnlyHint and a fully described schema, the description covers the return contents well, which matters because there is no output schema. The main gap is that it never clarifies whether reading marks the message as seen, which is a live ambiguity given the sibling mark_messages_seen.

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 the baseline is 3. The description adds only marginal parameter meaning, confirming the 'text' default for format (already stated in the schema). It does not need to compensate for schema gaps since the schema's parameter descriptions are already thorough.

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 verb and resource ('Read one message in full') and enumerates the contents (body, sender, recipients, attachments, per-recipient delivery status). 'One message in full' inherently contrasts with sibling list_messages, so an agent can distinguish them at a glance.

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 when-to-use, when-not-to-use, or alternative routing is provided. The description implies usage through its purpose but never says to use list_messages to obtain the ID first, nor clarifies when send_message or mark_messages_seen would be the right choice instead.

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