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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), and the description adds genuinely new context: results are limited to the *public* profile and each call costs 1 credit. It does not mention rate limits or failure behavior for nonexistent handles, so it is strong but not complete.

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?

Three short sentences, front-loaded with the resource identity, followed by what it returns, cost, and invocation constraint. No filler or repetition of the title.

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 the returned fields and discloses cost, so an agent knows what it gets back. The only gap is the undocumented `cache_max_age` parameter, which neither the schema nor the description explains.

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 67% and both `handle` and `url` are optional, so the description's 'pass either `handle` or `url`' resolves a real ambiguity the schema leaves open (mutual exclusivity/at-least-one). The undocumented `cache_max_age` parameter is not addressed, keeping it below a 5.

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 resource (public GitHub user/organisation profile) and enumerates the fields returned (followers, public repo count, bio, location, links), which separates it from siblings like github_followers or github_userRepositories. It does not explicitly name those siblings, so it stops short of a 5.

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?

'Pass either `handle` or `url`' gives invocation guidance, and the field list implies when this tool is appropriate versus the more specific github_* siblings. However, there is no explicit when-to-use/when-not or named alternative (e.g. use github_userRepositories for repo listings), so usage is only implied.

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