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 by structured data. The description adds value by disclosing exactly what data is computed (streaks, all-time vs 12-month contributions), which hints at a heavier aggregation call. It omits anything about caching, rate limits, or behavior for nonexistent/private users.

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 front-loaded sentence that identifies the subject before listing what it returns, with no filler or redundancy. It is somewhat long as a laundry list, but each item conveys a distinct piece of returned data.

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 carries the burden of explaining return values, and it does so thoroughly by enumerating the stat categories. For a single-parameter read tool with full annotation coverage, the main remaining gap is data freshness/auth behavior rather than core 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 coverage is 100% and the single username parameter is documented in the schema, including the @handle/URL formats and the organization exclusion. The description adds no additional meaning about the parameter. With one fully documented parameter, the baseline of 3 applies.

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 names a specific resource (a GitHub user's stats) and enumerates the concrete contents: contributions over 12 months and all time, streaks, biggest day, commits/PRs/reviews/issues since joining, top languages, and most-starred repos. That is far more specific than a restated title. It stops short of distinguishing this from siblings like get_github_wrapped or get_readme_card, so it is clear but not sibling-differentiating.

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 when-to-use guidance at all: no stated conditions for choosing this over get_github_wrapped or compare_github_profiles, and no prerequisites. The only scoping constraint (organizations aren't supported) lives in the schema, not the description. An agent must infer the tool's role from the output list alone.

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