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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds critical behavioral context beyond that: it emphasizes that this is retrieval, not authority, warns that vector search always returns the nearest neighbor and may appear confident even when incorrect, and describes the return format (passages with source, URL, and citation purpose). This is exactly the kind of context that helps an agent avoid misuse.

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 long but densely packed with essential information. It front-loads the primary use case and the critical warning, and repeats the 'do not use for decisions' point for emphasis, which is effective but slightly redundant. Every sentence adds value, and the structure is logical.

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?

The description covers the tool's purpose, limitations, and return value shape, and effectively routes to sibling tools. It does not describe parameter details (addressed above), but given the tool's simplicity, this is the only notable gap. It is otherwise complete for an agent to invoke it 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 description coverage is 0%, so the description must compensate, but it does not. It mentions 'semantic search' and implies a natural-language query, but does not explain 'top_k' (e.g., range, default, effect on result count) or any query formatting guidance. The purpose is clear, but parameter specifics are left entirely to the schema, which has no descriptions.

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 (search) and resource (knowledge base) and clearly distinguishes the tool from siblings by declaring it is for understanding, not deciding, and names the dedicated tools for policy and registration. It is unambiguous and actionable.

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?

Explicitly states when to use the tool (to understand how something works) and when not to use it (to decide anything), and names the alternative tools (GET /tld/:tld/policy and check_live) that take precedence. This provides clear routing with no inference needed.

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