patch_file

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

With no annotations provided, the description carries the full burden and discloses key behavioral traits: it automatically creates a backup and enforces uniqueness of the old_string. It does not mention error handling for non-unique matches or permission requirements, but the disclosed traits (backup, targeted modification) are valuable and not redundant with schema.

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 just two sentences, tightly written with no filler. It front-loads the primary action and includes the most critical constraints and side effects without unnecessary elaboration.

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 3-parameter tool with no output schema, the description covers the essential aspects: what it does, the uniqueness constraint, and the automatic backup side effect. It lacks explicit error-behavior details, but for this complexity level the description is sufficiently complete.

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%, and each parameter already has a clear description. The tool description reinforces the uniqueness requirement for old_string but does not add new parameter-level meaning beyond what the schema already provides, so the baseline of 3 applies.

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 uses a specific verb 'Replace' and a clear resource 'a specific string or block of code within a file', and adds the scope 'without rewriting the whole file' which distinguishes it from whole-file editing tools like edit_file. This makes the purpose unmistakable.

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 provides clear context for when to use the tool: for targeted, minimal changes without rewriting the whole file. It also states a critical precondition (old_string must appear exactly once), but it does not explicitly name alternatives or when-not-to-use scenarios beyond the implied whole-file rewrite exclusion.

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