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

Annotations already declare readOnly, idempotent, non-destructive, and non-open-world. The description adds genuinely useful context beyond them: that results are cached, that it does not trigger a live scan, and that it reflects exactly the two most recent scans. It omits pagination/limit behavior and result shape, but the annotations carry the safety profile.

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?

Two short, front-loaded clauses with no filler. The cost and read-only facts come first and the cached-vs-live constraint follows immediately.

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 simple read-only tool this covers the essentials, but with no output schema and an eight-value enum whose meanings are never explained, an agent cannot know what each type filter actually selects. The missing parameter semantics leave a real 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 description coverage is 0%, and the description says nothing about either parameter. The eight enum values (NEW, NOT_SEEN, OUTCOME_CHANGED, etc.) and the limit bound (1-50, default 20) are undocumented anywhere, so the description fails to compensate for the coverage gap.

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 ('inspect') and a precise resource ('changes observed between ProofRail's two latest autonomous MCP Radar scans'). It differentiates implicitly from mcp_radar_snapshot by noting it operates on cached results, though the sibling is never named.

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 a clear use context ('Cached results only') and an explicit when-not clause ('does not trigger a live scan'), plus a cost note ('FREE'). It stops short of naming the alternative tool (mcp_radar_snapshot) for triggering a live scan, leaving that inference to the agent.

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