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

Annotations already establish read-only/idempotent/non-destructive behavior. The description adds meaningful behavioral context: it returns top-N tools with full input schemas and curated examples, and explicitly states 'no second schema lookup needed.' This goes beyond the annotations and informs the agent of the exact return shape and direct-call readiness.

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 composed of four sentences that front-load the purpose and then add usage guidance and return details. The domain list is somewhat long but serves to clarify scope. It is efficient without being terse, though it could be trimmed slightly without loss of meaning.

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?

There is no output schema, but the description compensates by describing the return payload: 'top-N most relevant tools with names, descriptions, and full input schemas.' It also covers the primary use case and the 'call this FIRST' workflow. This is sufficient for a read-only discovery tool, though it omits mention of the `limit` parameter (covered in schema) and any error behavior.

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%, with each parameter (including aliases like q, task, search, description) documented in the schema itself. The tool description does not add new parameter semantics beyond what the schema provides, so the baseline of 3 is appropriate.

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 opens with a specific verb+resource: 'Find tools by describing the data or task.' It clearly distinguishes itself as a meta-search/discovery tool among siblings, and the enumerated domains (SEC filings, FDA drugs, etc.) further clarify scope. This is more than a tautology and immediately conveys what the 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?

The description explicitly states when to use: 'Use when you need to browse, search, look up, or discover what tools exist' and advises 'Call this FIRST when you have many tools available.' This gives a clear usage context. However, it does not explicitly mention when not to use it or name alternative tools, so it falls short of a 5.

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