pubmed_databases

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

The annotations already set readOnlyHint: true, so the read-only nature is disclosed. The description adds that it lists 'all available' databases, which clarifies the exhaustive scope, and notes the tool's purpose of discovering databases 'beyond PubMed'. However, it does not disclose return format, pagination, or any limitations (e.g., whether 'all' truly means complete). Given the annotation coverage, this is adequate but not rich.

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 function, the second gives practical use. No wasted words, information is front-loaded, and it is easy to parse. Every sentence earns its place.

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 simple, zero-parameter, read-only listing tool with no output schema, the description fully covers what the tool does and when to use it. It names the resource, gives examples, and states its purpose. There are no hidden parameters or complex behaviors to explain.

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 tool has zero parameters, so the description does not need to explain any. The schema coverage is 100% (empty properties). The description adds value by giving examples of what will be listed, but there is no parameter semantics to clarify. Per the rubric, 0 params gives a baseline of 4.

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 what the tool does: 'List all available NCBI Entrez databases (PubMed, PMC, Gene, Protein, etc.)'. The verb 'List' and resource 'NCBI Entrez databases' are specific, and the examples make the scope unambiguous. It also distinguishes this from sibling tools like pubmed_search or pubmed_fetch, which operate on specific databases rather than listing them.

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 gives clear context: 'Useful for discovering which NCBI databases exist beyond PubMed.' This implies when to use the tool (when you need to know available databases) and hints at its scope relative to other PubMed tools. It does not explicitly name alternatives or exclusions, but for a simple list tool with no parameters, this is sufficient.

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