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

Annotations already declare the safe read-only/idempotent profile, and the description goes beyond them with genuinely useful operational context: a 100/day shared free quota and an x402 paid fallback with URL and price. It also discloses the return shape (verdict, score, reasons, one-line recommendation). It stops short of explaining latency or what happens when a package is unknown.

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 the core question and verdict taxonomy, then inputs, then access/pricing. Every sentence carries information, though the quota/pricing sentence is more commercial than functional and could be trimmed without loss to an agent.

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?

For a three-parameter read-only check with no output schema, the description supplies the verdict vocabulary, the evidence categories, and the recommendation format, plus quota/pricing context. An agent has everything needed to call it and interpret the result without opening anything else.

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 67%, so the schema already documents most parameters including the version default and the ecosystem enum. The description's 'Input: name, ecosystem (npm | PyPI), optional version' largely restates the schema without adding syntax, constraints, or edge-case meaning. Baseline 3 is appropriate.

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 opening question plus 'One call, one verdict: safe / caution / avoid' states a specific action (safety assessment) and a concrete output shape, and the parenthetical lists exactly what signals are evaluated. It does not, however, distinguish itself from the sibling pkg_meta, leaving the boundary between 'safety check' and 'package metadata' to inference.

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 framing 'Is this package safe to install?' implies the pre-install decision context, but there is no explicit when-to-use, when-not-to-use, or routing to the sibling pkg_meta (which an agent could easily confuse for this). Usage is inferable rather than stated.

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