github_repos_get_readme

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

Annotations cover the safety profile (readOnlyHint, idempotentHint, openWorldHint), so the bar is lower, yet the description still adds real behavior: the content is returned already decoded to text, and GitHub auto-selects the preferred README among spelling variants. That is non-obvious behavior an agent would otherwise have to discover. It omits failure behavior when no README exists, keeping it short of a 5.

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, zero filler, with the core capability front-loaded and the sibling comparison following. Every clause earns 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?

For a simple read tool with no output schema, the description covers what is returned (decoded README text) and how the file is chosen, which is the key ambiguity. It does not note the error case when a repository has no README, a minor but real 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 coverage is 100% and all three parameters (owner, repo, ref) are documented in the schema itself, including the default-branch fallback for ref. The description adds no parameter-level detail, so the baseline 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?

States a specific verb and resource ('Get the repository's README') and immediately disambiguates from the closest sibling by naming `repos_get_content`. An agent can distinguish it from the generic content tool without opening either schema.

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?

Explicitly frames the tool as the way to avoid 'guessing at `repos_get_content`', which routes the agent to the right tool for README retrieval. It stops short of stating when NOT to use it (e.g., when you need a non-README file or raw bytes), so it is clear context rather than full when/when-not guidance.

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