batch_modify

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

With no annotations, the description fully carries the transparency burden. It discloses destructive behavior when `review:false`, the default `review:true` behavior (returns diffs without writing), per-file backups, and the rollback semantics of `all_or_nothing`. It also clearly states the tool does not find cross-file references.

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?

Although long, the description is densely packed and efficiently organized: purpose first, then usage context, then safety warning, then return shapes. Every sentence adds value—no filler or repetition. The careful structure makes it scannable despite its length.

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 description covers all critical aspects of a complex batch tool: purpose, usage boundaries, safety, transaction modes, review modes, return formats, and backup behavior. There is no output schema, so the description correctly includes the full return shapes for both `review:true` and `review:false` scenarios, leaving nothing an agent needs to infer.

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?

While the schema provides descriptions for `files`, `instructions`, and nested options, the description adds critical semantics: the meaning of `transactionMode` (rollback vs best-effort), the safety of the default `review:true`, and the exact return shapes for both review modes. This goes well beyond the schema's bare parameter definitions.

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 states a specific verb-resource pair: 'Apply the SAME natural-language instruction independently to each file in `files`.' It clearly distinguishes itself from siblings by naming `refactor` for cross-file edits and `modify_file` for single-file custom edits, leaving no ambiguity about scope.

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?

It provides explicit when-to-use guidance with concrete examples ('add JSDoc to every exported function', 'replace console.log with logger.info') and explicit when-not-to-use exclusions (cross-file references → `refactor`, single file → `modify_file`). It also explains when to choose `best_effort` vs `all_or_nothing`.

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