Reads a specified file and returns its contents as a string so AI agents can inspect source code and other files during development tasks.
This function will read the contents of a file and return it as a string.
| Name | Required | Description | Default |
|---|---|---|---|
| file | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description must carry the full burden. It merely restates the tool's name and basic action without disclosing error behavior, encoding handling, or safety properties. The description adds minimal value beyond the tool name itself.
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 a single, concise sentence that is front-loaded and directly states the action and return type. Every word is necessary and there is no 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 read tool with no output schema, the description does explain the return type (string). However, it lacks detail on edge cases like missing files, permission errors, or path interpretation, which an agent may need. It is adequate but not comprehensive.
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 only parameter 'file' has 0% schema description coverage, and the description does not specify whether it expects a path, URI, or file name. The description provides no additional meaning to the parameter beyond its name, leaving the agent to guess.
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 a file's contents and returns them as a string, which is a specific verb-resource pair. It distinguishes itself from siblings like write_file (write), grep (search), and glob (list files by pattern).
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 usage is implied: use when you need the full contents of a file. However, there is no explicit guidance on when not to use it or mention of alternatives like grep for searching, so it does not fully differentiate from sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.