read_file

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

With no annotations provided, the description carries the full burden of explaining behavior, but it does not mention error handling, permissions, encoding, binary-file rejection, or what happens if the path is invalid. The description only says it reads a text file, leaving several behavioral aspects undocumented.

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 mostly concise and front-loads the core purpose, but the final clause 'but this must work the same way for clients that can't' is somewhat redundant with the earlier conditional sentence. Still, it is not overly verbose.

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?

The tool is simple with one parameter and an output schema, so the description does not need to detail return values, but it omits important contextual details like error behavior and whether binary files are supported. It is adequate but not fully complete for an agent deciding whether to invoke it.

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, 'path', has no schema description, and the tool description only adds that it is 'any local path on the machine.' It does not clarify absolute vs. relative paths, path restrictions, or file-type handling, so the semantics are only partially explained.

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 text file'), the target resource ('at any local path on the machine'), and distinguishes it from sibling tools like read_image by specifying text files. This makes the tool's purpose immediately obvious.

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 explicitly explains when to use this server-side tool versus a client's own file tools, saying 'For a client that has no local filesystem access of its own... this is how it reads... a client with its own file tools (Claude Code) can use those instead.' This provides clear usage context.

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