docs_libraries

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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds real behavioral context: auto-indexing of unlisted packages, the meaning of default_for when env is omitted, and pagination defaults. It does not cover auth requirements or rate limits, which is a minor gap for a read tool.

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?

Front-loaded with the core purpose, then scope, usage, args and returns in a clean structure. The bilingual keyword line is retrievability padding but is short and clearly separated, and the Returns block earns its space since no output schema exists.

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?

With no output schema and 0% param documentation in the schema, the description supplies both the argument semantics and a full return shape (libraries, environments, jobs with their fields). An agent has everything needed to call and interpret this 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 0%, so the description must compensate, and it largely does: it enumerates valid ecosystem values, explains env as an id or project path that limits results, and gives limit's default (15) and max (200) plus offset's paging role. Those are exactly the details absent from the bare 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?

States a specific verb and resource ('List indexed libraries, exact versions and project environments') and enumerates the returned entity classes (libraries, environments, jobs), so an agent knows exactly what this tool surfaces. It does not explicitly contrast itself with docs_catalog, but the scope is unambiguous enough on its own.

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?

Gives concrete use cases: 'Use it to find an env id, or to follow a docset install / dependency indexing job.' It also clarifies the fallback path — unlisted packages are auto-indexed when api_lookup or api_check_code need them — which steers the agent away from unnecessary calls. No explicit 'do not use for X' exclusion is given, so not a full 5.

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