ncbi_esearch

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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses important runtime behavior: it returns formatted text with database-specific IDs, and it returns an error-prefixed text item on invalid database or query. It also warns about 70-80% recall loss without field tags, providing valuable behavioral context.

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 long and uses bolded warnings, emojis, and repeated emphasis on field tags, but it is well organized with clear sections and examples. The verbosity is justified by the critical impact of field tags on result quality, though some repetition could be trimmed.

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?

For a search tool with no output schema, the description covers the critical operational details: query format, field tag requirements, error behavior, and pagination parameters in schema. It does not mention NCBI rate limits or explain how the returned IDs are delimited, but the provided guidance is sufficient for successful invocation.

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 documents all eight parameters, so baseline is 3. The description adds meaningful query-construction semantics, including field tag syntax, boolean operations, and worked examples for the `query` and `database` parameters, going beyond the schema's brief descriptions.

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 action and resource: 'Search NCBI databases using E-utilities esearch API.' It clearly states the tool returns database-specific IDs, which distinguishes it from sibling tools like ncbi_esummary and ncbi_efetch.

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 provides strong, explicit guidance on how to construct queries, especially mandatory field tags for Gene and ClinVar, with concrete examples and performance consequences. It does not explicitly contrast this tool with sibling retrieval tools, but the context for when to search for IDs is clear.

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