Edit File

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

The description states that the tool is destructive (destructiveHint: true), line-based, and returns a git-style diff. It also notes the allowed-directory restriction, which adds behavioral context beyond the annotation. However, it does not mention whether the edits are applied atomically or if file locking is involved, but given the annotation already warns of destructiveness, the description provides sufficient extra clarity.

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 three sentences, each serving a distinct purpose: what it does, how it works, and a constraint. It is front-loaded and contains no fluff or repetition.

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 tool has 3 parameters, an output schema (for the diff), and annotations, the description covers the key aspects: operation type, line-based selection, exact matching requirement, diff output, and directory restriction. It does not explain the output format structure (though the output schema might handle that) or error conditions, but it is sufficiently complete for a tool with moderate complexity.

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 only 33%—the 'oldText' and 'path' parameters lack descriptions in the schema. However, the description clarifies that 'oldText' must be an exact match and that edits are line-based, adding meaning for the 'edits' and 'oldText' parameters. The 'path' parameter is not elaborated, but the tool's purpose implies it's a file path. The 'dryRun' parameter is described in the schema, so the description compensates for schema gaps reasonably well.

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 it performs 'line-based edits to a text file' and replaces 'exact line sequences with new content.' It distinguishes itself from the sibling 'filesystem__write_file' by specifying that edits are line-based and exact, and it also mentions it returns a git-style diff, which is a unique output format not shared by other file tools.

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 says 'Only works within allowed directories,' which provides a basic constraint but does not give explicit guidance on when to use this tool versus alternatives like 'write_file' for complete rewrites or 'move_file' for renames. No when-not-to-use or alternative tool names are mentioned, so it is adequate but not detailed.

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