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

Adds behavior the annotations cannot express: 'Costs US$0.005 in USDC on Base (x402)' discloses a payment/auth prerequisite that would otherwise fail silently, and 'nothing is executed' preempts the obvious fear about submitting malicious code to a security scanner. Consistent with readOnlyHint=true, destructiveHint=false, openWorldHint=true (fetches a URL).

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?

One front-loaded sentence: purpose, then threat list, then input modes, then cost and safety. Dense but every clause carries information; the run-on structure with parentheticals is slightly cramped but not wasteful.

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?

Covers the operation, invocation modes, cost, and the no-execution guarantee, and limits (max 50 files, 256 KB) live in the schema. What is missing is any hint of the response shape — verdict, findings, severity — which matters because there is no output schema to fall back on.

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%, so the baseline is 3; the description earns little extra. 'Paste the files or give one URL' does convey that files and url are mutually exclusive input modes, which the schema does not state, but the pinned/fingerprinting parameter is left entirely to the schema.

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 ('Check') against precisely enumerated resources (SKILL.md with scripts and references, AGENTS.md, CLAUDE.md, .cursorrules) and enumerates what it looks for: prompt injection, curl | bash, encoded commands, credential theft, exfiltration, hardcoded keys, persistence. The resource scoping alone differentiates it from audit_mcp_server, and the detection list goes well beyond a restatement of the name.

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?

'before loading it' gives a clear trigger moment, and 'Paste the files or give one URL' tells the agent how to invoke it. It stops short of naming siblings (audit_mcp_server, check_prompt_injection) or stating when not to use it, so the agent must infer routing from the target file type.

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