Read a file from GitHub

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

Annotations already declare readOnly/idempotent, but the description adds concrete behavioral details: returns content, sha, size, and latest commit, plus the 1 MB refusal. This goes beyond the annotations without contradicting them.

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?

The description is two sentences, direct, and informational. Every clause serves a purpose—stating the action, return values, and a constraint with an alternative. No redundant wording.

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 compensates by listing return fields. It also addresses edge cases (file size) and names the fallback tool. For a simple read operation, this provides complete context for an agent to invoke it correctly.

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 covers repo and ref with descriptions, but path lacks a schema description. The tool description implies path is a file path, but this is not fully explicit. Schema coverage is 67%, and the description adds only partial clarification, so a baseline score is appropriate.

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 the action ('Read a file (text) from a repository branch') and the resource (a file in a GitHub repo). It distinguishes itself from sibling tools like github_list_dir by focusing on file content retrieval.

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 explicit guidance on when not to use it ('Files over 1 MB are refused') and names the alternative tool (github_list_dir) for browsing. This makes the decision context clear without requiring inference.

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