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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds value beyond them by disclosing what is returned (summary, language, star/fork counts, link) and that results are sortable by stars/updated. It omits GitHub API rate-limit behavior, which is a real operational concern for a remote search.

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?

It is compact and front-loaded: purpose first, then use case, then a concrete example. The example largely duplicates the schema's examples array, so a small amount of space is not earning its place.

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 no output schema, the description usefully enumerates return fields, and the three parameters are fully covered by the schema. What is missing for a tool wrapping a remote API is rate-limit/error behavior and whether results are paginated, which keeps it from a 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?

Schema description coverage is 100%, with each of query, sort and per_page documented in the schema, so the baseline is 3. The description's example restates schema examples rather than adding new meaning about query syntax, sort tie-breaking, or how per_page interacts with paging.

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 gives a specific verb+resource ("搜索 GitHub 开源仓库") and goes further to describe sorting options and the returned fields (简介、语言、Star/Fork 数、链接). It is distinguishable from hacker_news_search and stackoverflow_search by resource, but it never names those siblings or explicitly contrasts with web_fetch.

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?

It states a clear context for use: finding open source projects, code libraries, or comparing library popularity. There are no explicit when-not conditions or named alternatives, which keeps it just 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.