patch_file

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

With no annotations, the description carries the behavioral burden. It proactively discloses three important traits: all occurrences are replaced, the operation uses atomic write, and the tool returns the number of replacements made. It does not spell out no-match or file-not-found behavior, but the core side effects and return signal are covered.

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 short sentences, front-loaded with the core action followed by the behavioral guarantee and return value. There is no redundancy or filler.

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 mutation tool with no annotations, the description covers the main behavioral contract and return semantics, and the input schema supplies the nested request fields and encoding default. The main gaps are explicit failure modes and when-not-to-use guidance, which are useful but not critical for invoking the tool.

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 100%, so the baseline is 3. The description adds value by explaining that the patch targets every occurrence of old_str, not just the first one, which is a semantic guarantee not explicit in the schema. Path and encoding are already fully described in the 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 begins with 'Apply a targeted patch to a file,' identifying a specific verb, target, and scope. It further defines the behavior as replacing all occurrences of old_str with new_str, which clearly distinguishes it from write_file (full-file overwrite) and read_file.

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 context is implied by the phrase 'targeted patch' and the find/replace semantics, but the description never explicitly says when to prefer patch_file over write_file or states any exclusions. An agent can infer the use case, but the guidance is not explicit.

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