Read repository file

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

Annotations already declare the tool is read-only and non-destructive. The description adds that it works without a local clone, which is useful context. It does not detail error handling, truncation behavior, or file existence checks, but with the annotations, this is adequate.

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, very concise, and front-loaded with the core functionality. Every sentence serves a purpose without redundancy.

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 file reading tool, the description covers the essential behavior and use case. It does not mention the max_chars parameter or output format, but the schema provides those details. Overall, it is complete for typical usage.

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?

The input schema already provides detailed descriptions for 4 of 5 parameters (80% coverage). The tool description adds no additional parameter information beyond that, making it sufficient but not exceptional.

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 tool returns file content at a specified ref, using a specific verb and resource. It distinguishes from sibling tools, which are focused on MRs, pipelines, etc., by being a file reading operation.

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?

The description provides a use case example ('.gitlab-ci.yml or configs without a local clone'), giving contextual guidance. It does not explicitly mention when not to use it or list alternatives, but given the sibling context, it is sufficiently clear.

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