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

With no annotations, the description carries the full burden. It discloses key behaviors: copies all rules, optional prefix, and automatic creation of a new mode declaration. Examples illustrate naming behavior. However, it does not mention side effects like file writing or output modes, which are left to the 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 well-organized with sections for purpose, when-to-use, features, and examples. Every sentence serves a purpose, and the examples are concise but informative. No fluff or redundancy.

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 7 parameters and no output schema, the description covers the core functionality thoroughly with examples. It does not explain all parameter interactions (e.g., grammar_content vs from_file, output_mode behavior), but the schema provides descriptions for those, so the overall context is sufficient for an agent to select and invoke 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 coverage is 100%, giving a baseline of 3. The description adds meaning through examples that clarify the relationship between source_mode, new_mode, and prefix_rules, including how prefixed rule names are generated. Other parameters are adequately described in the schema itself.

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 opens with 'Duplicate a lexer mode with all its rules,' using a specific verb and resource. It clearly differentiates from siblings like add-lexer-mode or move-rule-to-mode, which handle single modes or rules.

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 includes a 'When to use' section listing concrete scenarios: 'Creating similar modes, refactoring mode structure, creating mode templates.' It does not explicitly mention when not to use or alternative tools, but the context is clear.

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