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

Beyond the readOnly/idempotent annotations, the description adds critical behavioral details: it runs 134 diagnostic rules, returns a structured JSON array of diagnostics, returns an empty array for pass, and explicitly states 'writes no files and uses no network'. This provides far more context than the annotations alone.

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 compact yet information-dense, with clear section labels ('Use:', 'Inputs:', 'Effects:'). Each sentence contributes unique value—purpose, return format, usage guidance, and effects—without redundancy. It is efficiently structured for AI scanning.

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 purpose, usage, return value semantics, and non-effect guarantees, fully compensating for the single simple parameter. Given the tool's simplicity and the rich output schema/diagnostic format description, it is complete and self-sufficient for an agent.

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 already describes the one parameter 'source' thoroughly (full file, not fragment). The description's 'source is TypeScript DSL text' adds minimal new meaning. The mention of 'strictness options' is ambiguous since no such parameters appear in the schema, but schema coverage is 100%, so a baseline 3 is appropriate.

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 a specific verb+resource ('Validate a TypeScript intent definition') and immediately distinguishes from siblings by stating it does so 'without generating Swift' and explicitly comparing to 'swift.validate'. This makes the tool's unique role 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 'Use:' section gives explicit guidance: 'use for TypeScript DSL diagnostics before Swift output; use swift.validate for existing Swift.' This directly contrasts with an alternative sibling and clarifies when each should be chosen, fulfilling the highest bar for usage guidance.

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