open-context

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

No annotations provided, so description carries full burden. It discloses 'cache' behavior (important for idempotency/staleness concerns), but omits what specific data is returned (metadata, versions, deps?), error handling for invalid crates, or cache duration.

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?

Single efficient sentence with no waste. Front-loaded with action. However, extreme brevity leaves gaps in behavioral disclosure that could have been addressed with one additional sentence.

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?

Adequate for a simple 2-parameter lookup tool, but lacks description of return structure (critical for an 'info' tool) and caching policy details. No output schema compounds this gap.

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 has 100% description coverage with clear examples (serde, tokio). Description adds domain context ('crates.io') but does not elaborate on parameter formats or version string semantics beyond what the schema provides. Baseline 3 appropriate given schema completeness.

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?

Excellent specificity: verbs 'Fetch and cache', resource 'Rust crates', and source 'crates.io' clearly distinguish this from sibling tools like get_npm_info or get_python_info. The description precisely scopes the tool's domain.

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?

No explicit when/when-not guidance or comparison to alternatives (e.g., when to use get_npm_info instead). However, the naming pattern and 'crates.io' reference imply usage for Rust packages specifically. Implied usage only.

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