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

With no annotations provided, the description carries the full burden. It discloses determinism and cost ($0.001), which is helpful, but does not explicitly state whether the tool is read-only or has any side effects. The return format is described, but additional traits like error handling or limits are omitted.

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 two sentences long, front-loaded with the core purpose, followed by behavioral traits. Every word serves a purpose—no fluff or repetition. The structure is optimal for quick understanding.

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's simplicity, the description covers main aspects: purpose, return format, side effects (determinism), and cost. However, it lacks details on edge cases (e.g., no matches, invalid pattern), error messages, and output structure. The absence of an output schema increases the need for such details.

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, and the description does not elaborate on parameter meanings, constraints, or relationships. While 'pattern' and 'text' are self-explanatory, 'flags' is not described, and no guidance is given on format or validation beyond schema types.

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 tool's purpose: testing a regular expression against text and returning matches with capture groups. The verb 'Test' and the resource 'regex against text' are specific, and the tool distinguishes itself from siblings by its precise function.

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 implies usage for testing regex patterns but does not provide explicit guidance on when to use this tool versus alternatives (e.g., classify_text, extract_structured). No when-not or exclusions are mentioned, but the context is clear enough for a basic developer tool.

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