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

Annotations already declare readOnly/openWorld/idempotent, so the bar for added transparency is lower. The description adds substantial behavioral context beyond annotations: 'Blocks localhost/private IPs' is a critical safety disclosure; 'quick ~1–3s; scan_depth=deep for secret scan (~8–12s)' discloses timing; '6 credits hosted' discloses cost; 'Read plain_summary first; only drill into security_headers or secrets if grade is poor' gives a workflow behavior. All traits are consistent with the readOnly hint, so no contradiction.

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 dense but every sentence earns its place: state purpose, list outputs, provide reading strategy, timings, credit cost, when-to-call, safety block, exclusions, an example, and read-only reminder. It is front-loaded with the most important information and uses semicolons to keep it tight. For a tool with 18 parameters, this is appropriately concise.

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 the essential context needed to safely and effectively invoke the tool: input constraints (public HTTPS URL), output summary (security grade, SSL, etc.), safety (blocks localhost/private IPs), cost (6 credits), performance expectations (quick vs. deep), usage flow (read plain_summary first), and a concrete example. Since there is no output schema, the description appropriately outlines the key return categories. The 18-parameter schema plus rich annotations make this complete.

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% (18/18 parameters have descriptions), so the baseline is 3. The tool description mentions 'scan_depth=deep for secret scan' but the schema already explains deep scan behavior in the 'scan_depth' parameter description. No additional parameter semantics are provided beyond what is already in the schema, so the score stays at the baseline.

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 and resource: 'Audit a public HTTPS URL the user deployed — security grade A–F, SSL, headers, cookies, health, exposed secrets, tech stack.' This clearly states what the tool does and enumerates its outputs. It also distinguishes from siblings with explicit exclusions: 'NOT for repo code (find_code), packages (check_package), tests (check_test), or project layout (get_project_context).' This is a model of purpose clarity.

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 gives precise when-to-use guidance: 'Call when user pastes a live URL — post-deploy check, is it secure, what framework, exposed keys.' It also provides an example call and explicitly names alternatives for non-matching cases, such as 'repo code (find_code), packages (check_package), tests (check_test), or project layout (get_project_context).' This is comprehensive usage direction.

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