list_messages

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

Annotations already declare readOnlyHint=true and destructiveHint=false, indicating a safe read operation. The description adds valuable behavioral context beyond annotations: default pagination (latest 20), date range limit (183 days), and critical handling instructions for presigned URLs ('Do not parse, modify, or re-encode them'). It doesn't mention rate limits or authentication needs, but provides useful operational details.

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 overly verbose and repetitive with eight consecutive 'If you want...' sentences that duplicate schema information. While front-loaded with important behavioral details, the parameter listing adds unnecessary length without corresponding value. The structure could be significantly streamlined.

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 the tool's complexity (11 parameters) and lack of output schema, the description provides good coverage of key behavioral aspects (pagination defaults, date limits, URL handling). With annotations covering safety and high schema coverage for parameters, the description adds necessary context about operational constraints, though it could better explain the return format.

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?

With 91% schema description coverage, the schema already documents most parameters thoroughly. The description adds minimal semantic value by listing parameter purposes in a repetitive 'If you want...' format, but doesn't provide syntax examples, format details, or constraints beyond what's in the schema. The baseline 3 is appropriate given high schema coverage.

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 tool's purpose as 'List Messages' with specific details about default behavior (latest 20 messages) and date range limitations. It distinguishes from siblings by focusing on listing rather than creating, deleting, or getting specific messages, though it doesn't explicitly name alternatives like 'get_message' or 'get_recent_messages'.

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 provides implied usage guidance through parameter explanations (e.g., 'If you want to get messages from a specific date range...'), but lacks explicit when-to-use vs. when-not-to-use statements or named alternatives. It doesn't clarify when to choose this over 'get_recent_messages' or 'get_message' from the sibling list.

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