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

Annotations already declare readOnlyHint and idempotentHint true, and destructiveHint false. The description adds useful behavioral context: 'with user authorization' (an operational requirement) and 'Safety: Search derived Promise memory, not raw provider mailboxes' (data source scoping). No contradiction with annotations; adds value beyond the structured hints.

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 sentences, front-loaded with the action ('Search Promise's derived memory'). The safety note is extra but directly relevant. No fluff; concise. Slightly could be more structured, but it's efficient.

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 search tool with 2 parameters and no output schema, the description provides no parameter guidance, no result format, and no pagination info. Annotations cover safety but not operational details. The description is too minimal for an agent to confidently invoke it correctly with distinct queries and limits.

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 0%, meaning the description must compensate for parameter meaning. The description does not mention 'query' or 'limit' at all, leaving the agent to infer from parameter names alone. With only 2 parameters, it could easily add semantic detail (e.g., query format, limit purpose) but doesn't.

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 'Search Promise's derived memory' – a specific verb and resource. It adds scope by noting 'with user authorization' and distinguishing from 'raw provider mailboxes'. However, it doesn't name a specific sibling tool to differentiate, so it doesn't fully leverage sibling awareness.

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 when to use (searches on derived memory) and includes an exclusion ('not raw provider mailboxes') but doesn't explicitly mention alternative tools or conditions for selection. The context is clear but lacks concrete 'when to use vs. when not to use' guidance.

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