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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds only the useful scoping fact that results are 'public' accounts; it says nothing about rate limits, pagination caps, or result volume, which for an open-world search endpoint would be valuable context.

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 tight sentences, front-loaded with the core action; the second sentence earns its place by routing to follow-up tools. 'Results contain matching user profiles' is mildly redundant given the output schema exists.

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 annotations covering safety, 100% schema coverage, and an output schema handling return values, the description supplies the remaining decision-relevant context (public-only, discovery-then-detail workflow). Only pagination/volume expectations are absent, which is a minor gap.

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 5 documented parameters, so the schema carries the semantics. The description's 'username or profile query' loosely maps to q but adds no syntax, qualifier, or default information beyond what the schema already states.

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: 'Search public GitHub accounts by username or profile query.' It is clearly distinguishable from github_search_repositories (repos) and from detail siblings like github_user_followers, though it never names github_user, the exact-lookup counterpart an agent must choose between.

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 a concrete use context — 'use this to discover accounts before requesting followers, following, or organization details' — which routes the agent toward github_user_followers, github_user_following and github_org as follow-ups. It lacks an explicit when-not-to-use clause (e.g. 'if you already know the login, call github_user directly').

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