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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, but the description adds substantial context: returned facts are dated rather than scored, status values are enumerated, registry/package/scanner checks are summarized, and each response ends with a source block including license and retrieval time.

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 front-loads the core purpose and accepted inputs before detailing return categories. Every sentence carries useful information, though the long unpacking of return fields makes it slightly heavier than necessary for a concise lookup.

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?

With no output schema, the description adequately explains what is returned: dated status, registry, package, scanner, and agent-report facts, plus the source block. It also covers menu behavior and the absence-of-data caveat, leaving no major gaps for correct invocation.

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 schema documents both parameters. The description still adds value by explaining the purpose of key menu choices, e.g. 'install-check' as the facts used before installing and 'change-watch' for recent changes, beyond the enum listing.

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 states a specific verb and resource: 'Look up recorded facts about an MCP server.' It further clarifies the lookup targets (registry name, short name, package) and distinguishes the output from scores, so an agent can tell exactly what the tool does.

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?

It explicitly frames the tool's use case ('before installing or connecting to it'), explains accepted target formats, and describes when to choose each menu option such as 'install-check' or 'change-watch.' The caveat that 'absence of data says nothing' is a useful usage constraint.

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