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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the agent knows it's a safe, open-ended read. The description adds one useful behavior detail: 'Returns top results by stars,' but it does not mention result limits, pagination, or other operational specifics. This adds some context beyond annotations but remains limited.

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 with zero waste. It front-loads the action and resource, then adds the key behavioral detail about star-based ranking. Perfectly concise for a tool with one parameter.

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?

Given the tool's simplicity—one parameter, clear annotations, and no nested objects—the description covers the essential behavior. The absence of an output schema does not require a detailed return description per the rules, and the star-ranking note provides sufficient context. A slightly richer mention of result count or sorting options would push it to 5.

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?

The schema provides 100% coverage for the single 'query' parameter with an example ('mcp server typescript'). The description's 'matching a keyword' adds no new meaning, so the baseline score 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 clearly states the action (Search), resource (GitHub repositories), and scope (matching a keyword). It distinguishes itself from the sibling extract_* tools by focusing on keyword-based search rather than extraction from specific sources.

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 implies the use case—searching repos by keyword—but does not explicitly state when to use this over alternatives or when not to use it. With many sibling extract tools, a note on preferring this for broad repo discovery would be valuable.

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