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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds valuable behavioral context: 'Returns the top-N most relevant tools with names, descriptions, and full input schemas... no second schema lookup needed.' This explains the output format and convenience, going beyond the annotations.

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 a single paragraph of 4-5 sentences. It is front-loaded with the primary purpose and provides examples. It is concise without being overly terse, though it could be slightly more structured (e.g., bullet points).

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 compensates by explaining what the tool returns ('top-N most relevant tools with names, descriptions, and full input schemas'). It also specifies when to use it ('FIRST'). It does not cover error handling or no-result scenarios, but it is adequate for a discovery tool.

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 baseline is 3. The description mentions 'query' and lists example queries but does not add significant new meaning beyond the schema's parameter descriptions. The aliases are already in the schema.

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 purpose: 'Find tools by describing the data or task.' It provides a specific verb (discover) and resource (tools). It distinguishes from siblings by advising to call this first when many tools are available, setting it apart from other search/research tools.

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 says 'Call this FIRST when you have many tools available and want to see the option set', providing clear context. It lists domains (SEC filings, financials, etc.) to indicate when the tool is appropriate. While it doesn't explicitly state when not to use it, the guidance is strong enough.

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