crates_metadata

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

No annotations are provided, so the description carries the full burden. It discloses key behavioral traits: it returns metadata but 'Does NOT include full documentation content,' clarifies what the response includes (e.g., URLs for docs.rs and GitHub), and mentions that outputs can be passed to other tools (WebFetch, GitHub provider). However, it doesn't cover potential errors, rate limits, or authentication needs, leaving some gaps.

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 well-structured with clear sections (purpose, usage guidelines, returns, details, args, returns, example). Each sentence adds value, such as clarifying exclusions ('Does NOT include full documentation content') and providing actionable context ('can be passed to WebFetch'). There is no redundant or wasted text, making it efficient and easy to parse.

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 no annotations and no output schema, the description does a good job covering the tool's behavior, parameters, and return details. It lists what the response includes and provides an example. However, it doesn't explicitly mention error cases (e.g., invalid crate names) or potential limitations (e.g., network failures), which would enhance completeness for a tool with no structured output schema.

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. It provides a dedicated 'Args' section explaining the single parameter 'crate' with examples ('serde', 'tokio', 'actix-web'), adding meaning beyond the schema's minimal title. The description fully documents the parameter's purpose and format, effectively compensating for the lack of schema 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 clearly states the tool's purpose: 'Get detailed metadata for a specific Rust crate from crates.io.' It specifies the verb ('Get'), resource ('Rust crate'), and source ('crates.io'), distinguishing it from sibling tools like npm_metadata or pypi_metadata that target other ecosystems. The description is specific and avoids tautology.

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 includes an explicit 'USE THIS WHEN' section: 'You need comprehensive information about a specific Rust crate.' It distinguishes this tool from search_crates (which likely returns multiple results) and fetch_*_docs tools (which retrieve documentation content). The guidance is clear and provides context for when to use this tool versus alternatives.

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