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

Annotations already disclose readOnly, idempotent, and non-destructive behavior. The description adds valuable behavioral context by describing the return format: 'names, descriptions, and full input schemas (with curated examples) — each result is ready to call directly, no second schema lookup needed.' This tells the agent exactly what to expect from the output, beyond what annotations provide.

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 efficient and front-loaded with the core purpose. The extensive list of data domains is somewhat verbose but serves the practical purpose of helping users formulate queries. The second sentence adds essential output details and usage guidance. No filler words, though the domain list could be trimmed for extreme conciseness.

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 that there is no output schema, the description fully compensates by detailing the return value: tool names, descriptions, full input schemas, and curated examples. It also covers the decision-making context ('Call this FIRST') and the breadth of domains. For a read-only discovery tool with strong annotations, this description is complete and well-suited for an agent to invoke 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 100%, so the baseline is 3. The description mentions 'describing the data or task' which aligns with query parameter, but does not add detail beyond the schema's own descriptions of query and aliases. The concept of 'top-N' subtly references the limit parameter, but no new semantic information is provided in the description.

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 function: 'Find tools by describing the data or task.' It goes beyond a generic verb+resource by enumerating specific data domains (SEC filings, FDA drugs, FRED, etc.), which distinguishes it from all sibling tools that are domain-specific or task-specific. No ambiguity about what this tool does.

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: 'Use when you need to browse, search, look up, or discover what tools exist,' and 'Call this FIRST when you have many tools available and want to see the option set (not just one answer).' This provides clear context and an implicit exclusion (if you know the exact tool or need a single answer, you wouldn't use this).

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