Read File

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, setting clear safety expectations. Description adds behavioral context: supports text and binary files (Base64 return), handles encoding, and line limits, which goes beyond annotations.

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?

Description is concise and structured with Args, Returns, and Examples sections. Front-loaded with primary action. Slightly redundant with schema but clear.

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?

Given the schema covers parameters fully and annotations provide safety profile, the description adequately covers behavior and return. However, missing explicit info on possible errors (file not found, permission) and output schema details (since no output schema exists, description could elaborate on return structure).

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%, so the schema already documents parameters. Description repeats path, encoding, and max_lines but adds examples and default value clarification. No additional semantic detail beyond 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?

The description clearly states the tool reads file content, with specific verb and resource. It distinguishes from write tools and editing tools, but not from multiple file read (fc_read_multiple_files) which exists among siblings.

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?

Description implies use for reading file content but does not provide guidance on when to use vs alternatives like fc_read_multiple_files or fc_file_info. No explicit when-not-to-use or prerequisites.

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