Read a GitHub source file

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

Annotations already declare readOnlyHint and idempotentHint. The description adds context about using the GitHub contents API and token requirements, which is helpful. It could mention potential truncation or pagination via offset parameter, but overall adds value beyond annotations. No contradiction.

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 concise sentences with no waste. The first sentence gives purpose and API, the second gives token guidance. Could be improved by structuring parameter listing, but still efficient.

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 tool with 6 parameters (3 required), no output schema, and sibling tools, the description is incomplete. It does not explain key parameters like owner, repo, path, or the truncation behavior via offset. Missing details that would help an agent handle large files or failures.

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 only 33% (descriptions for offset and maxChars). The description adds no parameter details; it only mentions GITHUB_TOKEN which is not a schema parameter. The remaining parameters (owner, repo, path, ref) are left unexplained, failing to compensate for low coverage.

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 clearly states 'Reads one file from a GitHub repository using the GitHub contents API', specifying the verb and resource. It implicitly distinguishes from sibling tools like read_web_source or read_local_source by targeting GitHub, but does not explicitly contrast with them.

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?

Provides token guidance (optional for public, required for private), giving some usage context. However, it does not indicate when to use alternatives or any exclusions.

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