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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds substantial context beyond them: no account/API key needed to build, runner + CI access + PB_CUSTOM_TESTS_FILE required to run, checks are case-insensitive text comparisons that do not judge meaning or verify backend actions, invalid packs raise a validation error, and test content is not stored or executed while request metadata is logged.

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?

Front-loaded with purpose and output, then usage, then prerequisites, then check semantics. Every sentence carries content, though the density of constraints makes it longer than strictly necessary for a one-parameter tool.

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?

With no output schema, the description correctly explains the return value (JSON text to save as tests.json) and the failure mode (tool error on invalid packs). Combined with the prerequisites and check semantics, an agent has everything needed to call it correctly.

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 description coverage is 100% and there is a single parameter, so the schema already documents items, required fields, maxItems, and case-insensitive comparison. The description restates the 1-20 bound and the case-insensitive/whitespace behavior but adds no syntax or format detail the schema lacks.

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?

States a specific verb and resource ('Validate 1-20 response tests') plus the concrete output ('return JSON text to save as tests.json for PromptBrake CI'). It explicitly distinguishes itself from the sibling map_owasp_llm_risk, so an agent can route correctly without opening schemas.

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?

Names the triggering condition ('when the user has prompts and expected or forbidden response text') and the alternative for the other case ('use map_owasp_llm_risk for risk-based test ideas'). It also clarifies the no-account path versus the separate execution prerequisites, which is real routing information.

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