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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description reinforces this with 'Read-only: never modifies the scanned target' and adds meaningful behavioral detail about the four checks performed and the nature of the output. This goes beyond the annotations without contradicting them.

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?

Every sentence earns its place: the operation, the checks, the output, the recommended usage window, and the read-only guarantee are all covered in a compact, well-front-loaded description. No filler or redundancy.

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?

Given the output schema, annotations, and fully described parameters, the description provides all the context an agent needs: what the tool does, what it returns, when to run it, and that it is non-destructive. The sibling tool distinction is lightly handled but sufficient.

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%, so the schema already documents both parameters. The description adds general context about typosquat detection, which loosely relates to package_name, but it does not add parameter-level meaning beyond what the input schema already provides. 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?

States a specific verb ('security-scan'), a clear resource ('MCP server or skill package'), and names the exact checks and outputs (0-100 score, letter grade, detailed findings). This clearly distinguishes it from the sibling trust_scan_file by targeting packages/directories rather than single files.

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?

Gives explicit timing guidance: 'Run this on any directory BEFORE wiring it into your agent.' This tells the agent when the tool is appropriate. It does not explicitly name trust_scan_file as the alternative for single files, but the directory/package framing implies the distinction.

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