APIbase

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It fails to mention whether results are cached, rate limits, authentication requirements, or what the response structure looks like. The only behavioral hint is 'Unique capability for research agents' which identifies the target use case but not operational characteristics.

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, efficiently structured sentence using an em-dash to separate the core function from use cases. Every clause earns its place: the function (find similar), the mechanism (semantic), use cases (competitors/alternatives), and differentiation (without knowing keywords).

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 5 simple parameters with full schema coverage and no output schema, the description adequately covers the tool's purpose. However, with no annotations and no output schema, gaps remain regarding return format, pagination behavior, and error conditions. It meets minimum viability but lacks richness.

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?

With 100% schema description coverage, the schema already documents all parameters adequately. The description mentions 'given URL' which maps to the url parameter, but does not add syntax details, format examples, or semantic context beyond what the schema already provides. Baseline 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 uses specific verb 'Find' with resource 'web pages' and mechanism 'semantically similar to a given URL'. It clearly distinguishes this from keyword search via 'without knowing what to search for' and identifies the provider (Exa), differentiating it from sibling search tools like search.google.web.

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 phrase 'without knowing what to search for' provides clear context for when to use this tool versus keyword-based alternatives. However, it does not explicitly name specific sibling tools (e.g., search.google.web) as alternatives or provide explicit when-not guidance.

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