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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered. The description adds real value by listing what the response contains, which matters since there is no output schema, but it omits behavior for a nonexistent version or invalid version string.

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?

A single sentence with the verb and resource front-loaded and zero filler. The parenthetical clarifications of Hex.pm and Elixir/Erlang each earn their place by disambiguating the ecosystem.

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 two-required-parameter read tool with full schema coverage, complete annotations and no output schema, the definition covers purpose and return content adequately. Only the miss on failure behavior for an unknown version keeps it short of full completeness.

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% and both parameters carry examples and descriptions, so the schema does the heavy lifting. The description adds no format or validation detail for name/version beyond what the schema shows, which is the expected baseline.

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: get details for a specific version (release) of a Hex.pm package, with the Elixir/Erlang clarification. The phrase 'specific version (release)' implicitly separates it from the package-level sibling hex_pm_get_package, but no sibling is named, so differentiation is inferred rather than explicit.

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?

There is no explicit when-to-use or when-not-to-use statement, and no alternative is named. The enumerated return fields (dependency requirements, docs availability, publisher, downloads) do imply the lookup scenario, which is enough for implied usage but leaves routing between get_package, list_releases and get_release to inference.

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