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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so the description's job is to add what they cannot. It does: result ordering (newest first), the fields returned (date, link, excerpt, breaking flag, compare link), the two data sources (GitHub releases, then changelog fallback), and the meaning of the 'complete' flag when sources don't span the range.

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?

Front-loaded with purpose and examples before mechanics, and every sentence carries signal (sources, fallback, completeness flag). It is dense and runs long for a single paragraph, but there is little that could be cut without losing routing or output context.

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?

With an output schema present, the description needn't explain returns, yet it still describes ordering, fields, fallback sources, and the completeness caveat. For a 5-param, read-only lookup with a clear default and an explicit exclusion, nothing an agent needs to call it correctly is missing.

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 100%, so the baseline is 3, but the description adds real meaning: name is an npm/PyPI package whose latest release names the GitHub repo, repo is an alternative or complement to name, toVersion defaults to latest, and notes start after fromVersion. Defaults and inter-parameter relationships go beyond the field-level schema text.

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+resource ('Get release notes') and immediately scopes it with two concrete user-question examples, so an agent recognizes the intent instantly. It also excludes a nearby-but-wrong use case ('Not for vulnerabilities'), which cleanly separates it from siblings like check_license or get_eol_status.

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?

Gives explicit when-to-use triggers ('what changed between two versions', 'what to watch for in an upgrade'), worked query phrasings, and an explicit when-not ('Not for vulnerabilities'). Required vs optional inputs are framed (fromVersion is what the user has; toVersion defaults to latest).

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