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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description does not contradict these. It adds useful behavioral context by detailing the exact return structure (every version string paired with timestamp plus total count), which goes beyond the annotations.

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 three sentences, each earning its place: first states the resource and scope, second details the output, third answers the key use case. It is front-loaded and free of fluff.

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 tool with one parameter, an output schema, and read-only/idempotent annotations, the description is complete. It explains the input, output, and purpose without redundancy. No further context appears necessary.

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 100% (the 'name' parameter is described as 'vendor/package'), so the baseline is 3. The description adds a concrete example (symfony/console) and reinforces the format with 'given a vendor/package name', providing a small but meaningful boost beyond the 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?

The description clearly states a specific verb ('returns') and resource ('release history of one PHP/Composer package on the Packagist registry'), and it specifies the output (every version string with release timestamp and total count). It distinguishes itself from sibling tools like get_package or package_stats by focusing solely on version history.

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 on when to use the tool ('Answers which versions of a Composer package exist and when the latest one shipped') and provides an example input format. However, it does not explicitly mention exclusions or alternatives, so it falls short of a 5.

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