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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the description does not need to restate those. It adds valuable behavioral context by disclosing that results include names, descriptions, and full input schemas with curated examples, and that each result is ready to call directly with no second lookup. This informs the agent of the exact response structure and immediate actionability, 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 front-loaded with the core purpose, followed by a scannable domain list, then return-behavior details, and a clear 'call this FIRST' instruction. It is somewhat long due to the enumerated domains, but every sentence contributes useful information. It strikes a good balance between completeness and length, though the domain list could be seen as slightly verbose.

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?

With no output schema, the description appropriately explains what the tool returns: top-N tools with names, descriptions, and full input schemas. It also sets expectations with 'ready to call directly' and 'no second schema lookup'. It does not mention pagination or error handling, but for a discovery tool with clear annotations and a well-documented limit parameter, the description covers the essential context.

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?

The input schema already provides 100% coverage with detailed descriptions for query, its aliases (q, task, search, description), and limit. The description adds only high-level context ('describing the data or task', 'top-N') that maps closely to existing schema descriptions. Therefore, the description adds minimal value beyond the schema, warranting the baseline score of 3.

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 opening sentence 'Find tools by describing the data or task' uses a specific verb and resource, clearly distinguishing this as a meta-tool for discovery rather than a data-access tool. The scope is further clarified with a long list of domains (SEC filings, FDA drugs, etc.), and the 'Discover Tools' title is reinforced. This clearly separates it from sibling tools like search_datasets or query_layer.

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 'Call this FIRST when you have many tools available...'. It also implies a boundary with 'not just one answer', indicating it is for exploring options rather than directly retrieving a known answer. However, it does not explicitly identify when not to use it or name alternative tools, so it stops 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.