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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: it says which fields are returned by default (name_version, summary, pip_command, sidebar, description), which tells the agent how the optional 'fields' parameter will behave. Auth, rate limits, and error behavior remain unstated.

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?

Two sentences, front-loaded with the action and output list, with no filler. The parenthetical cross-reference is slightly extraneous but cheap and informative. Dense and well ordered.

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?

There is no output schema, so the description usefully enumerates the returned fields and their defaults, which is what an agent needs most here. The remaining gap is the unexplained 'limit' parameter. For a simple 3-parameter read tool with full annotation coverage, this is close to complete.

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 coverage is 67%: 'name' has an example, but 'limit' is completely undocumented in both schema and description. The description partially compensates by naming the default returned keys, which clarifies the intent of the 'fields' parameter, but it says nothing about 'limit' or how many results/items it bounds. Baseline 3 is appropriate.

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 gives a specific verb and resource ('Get a package's PyPI page for its latest version') and then enumerates exactly what comes back (name/version, summary, pip install command, links, sidebar, README). It also maps itself to an equivalent sibling command (clify_run site=pypi command=get-package), so an agent can place it precisely without opening the schema.

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?

Usage is implied by the resource scope (fetch PyPI metadata for a package) and the parenthetical notes the equivalent clify_run invocation, but there is no explicit when-to-use/when-not guidance, no comparison against crates__get-crate for non-Python packages, and no stated prerequisites. Adequate but thin.

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