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

Annotations already declare readOnlyHint=true, and the description restates 'Read-only' (no incremental credit). It does add real behavioral context by enumerating the probe steps (token mint, API reachability, repository access) and stating that each check's outcome is reported, which tells the agent this tool performs live network probing of a credential.

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, no filler, with the core action and probe breakdown front-loaded and the applicability constraint immediately following. Every clause carries information.

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?

For a single-parameter, read-only diagnostic with no output schema, the description covers what is checked and that per-check outcomes are returned, plus the credential-type restriction. Nothing needed to invoke it correctly is missing.

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% and there is only one parameter, so the schema already documents credential_id as a UUID. The description marginally adds by constraining which credentials are valid inputs (GitHub App backed only), which is a semantic restriction not encoded in the schema.

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?

Names a specific verb (verify), a specific resource (GitHub App credential), and the mechanism (probing the installation with token mint, API reachability, repository access). The added constraint 'Only works for GitHub App backed credentials' distinguishes it from sibling credential tools like get_github_credential_activity, get_github_credential_usages, and replace_github_credential without requiring the schema to be opened.

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?

States a clear applicability condition — only GitHub App backed credentials — which functions as an exclusion for the agent. It does not, however, name an alternative for other credential types (e.g., validate_credential_name) or state when a verification should be triggered versus reading credential activity.

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