fs_file_replace

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

With no annotations, the description bears full responsibility for behavioral disclosure. It mentions 'in-place' (mutation) and return count, but lacks details on error handling, whether all occurrences are replaced, and the role of line_separator. This is insufficient for a destructive operation.

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 only six words, making it highly efficient and front-loaded. While very brief, it avoids redundancy and conveys the core action and return value. It could be slightly more informative without losing conciseness.

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 file mutation tool with four parameters and no annotations, this description is severely incomplete. It omits critical context such as file handling, match semantics, and the line_separator parameter's purpose. The presence of an output schema mitigates the need to detail return format, but other gaps remain.

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 input schema has 0% description coverage, so the description must clarify parameter meanings. It only implies search_term and replacement via 'text replace' but does not explain file_path or line_separator, leaving them ambiguous.

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 operation ('in-place text replace') and the unique return value ('matched line count'). This distinguishes it from sibling tools like fs_write_text (whole-file write) and fs_search_in_file_by_content (read-only search).

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?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites such as file existence, nor does it explain when to choose this over fs_write_text or search tools.

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