Read Media File

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

Annotations provide readOnlyHint=true, and the description adds behavioral details such as base64 encoding, MIME type determination, and handling of image/audio vs other file types. It also mentions directory constraints, adding value 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?

The description is contained in a single sentence that front-loads the purpose. It is succinct without waste, but could benefit from slightly more structure (e.g., separate sentences for constraints).

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 output schema exists, description does not need to detail return values. However, it lacks full context about file size limits, allowed MIME types specifically, and clear differentiation from similar siblings (read_file, read_text_file). Adequate but incomplete.

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 description coverage is 0%, so the description must compensate. It only mentions 'within allowed directories' for the path parameter, but does not explain path format, absolute/relative, or any additional constraints. The schema only defines path as a string, leaving ambiguity.

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 'Read a file and return it as a base64-encoded content block with its MIME type', specifying the exact action and output format. It distinguishes from siblings like read_file or read_text_file by emphasizing base64 encoding and MIME type handling.

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 only notes 'Only works within allowed directories' but does not provide explicit guidance on when to use this tool versus alternatives. It lacks 'when-not' or comparison to sibling tools.

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