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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds a critical operational dependency: 'Requires OPENAI_API_KEY'. It also clarifies the underlying technique (vector embeddings), which is behaviorally relevant, compensating for the lack of error/rate-limit details.

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 two sentences: the first states the core purpose and method, the second adds the key dependency and a differentiating attribute. No filler words or redundant restatements.

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 the rich annotations, full schema coverage, and an output schema, the description covers essential operational context (read-only conceptual search, API key requirement). It doesn't discuss pagination or filters, but those are fully specified in the schema, so the description is sufficient for an agent to select and invoke the tool 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%, with all 9 parameters documented including defaults, ranges, and examples. The description adds no parameter-specific details beyond the schema, so the baseline 3 applies.

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 'Search the Urantia Book using semantic similarity (vector embeddings)' with a specific verb, resource, and method. It also distinguishes from exact keyword search by noting it returns results 'even without exact keyword matches', which separates it from sibling search.fulltext.

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 implies usage for conceptual queries rather than exact-match search via 'even without exact keyword matches'. However, it does not explicitly name an alternative like search.fulltext or state when not to use the tool, so it stops short of full exclusion guidance.

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