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

Goes well beyond the readOnly/openWorld annotations by disclosing per-call pricing ($0.004 USDC via x402 across Base/Solana/Polygon/Arbitrum), auto-payment for x402 MCP clients, the 20-package cap, upstream sources (deps.dev, OSV.dev, registries), and exactly which risks are flagged (slopsquatting, malware, typosquats, CVEs, yanked/deprecated versions, install scripts).

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?

Dense but front-loaded: purpose, limits, decision model, and risk coverage come before pricing and the sample. The payment and free-sample sentences are long but load-bearing for an x402 tool, so little is truly wasted.

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?

There is no output schema, and the description still conveys the return shape at a semantic level (one decision per package with reasons) along with input limits and manifest support. The precise field-level response structure is left implicit, which is the only gap.

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, but the description adds real value: accepted ecosystem prefixes, worked string examples ("express@4.17.1", "pypi:requests==2.31.0", "cargo:serde"), the ability to paste a package.json or requirements.txt as a manifest, and the note that npm version ranges are resolved like npm.

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 (check dependencies before install) plus the decision outputs (ALLOW/CAUTION/BLOCK with reasons). No sibling tool performs package/dependency scanning, so the agent can confidently route here without further comparison.

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?

Explicitly frames the trigger: run before a coding agent installs packages, with a concrete free-sample input. It does not name when-not-to-use or a companion alternative such as cve_lookup, so it stops short of full routing guidance.

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