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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description adds genuinely new behavioral context: it is paid per server, 'reads the map only' (implying no live server contact), and returns one of four per-tool states including risk escalation on changes.

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 purpose, then mechanics, then cost and side-effect notes; every clause carries information. It is dense and slightly run-on, but no sentence is 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?

With no output schema, the description compensates by enumerating the return classifications (unchanged, changed with risk rise, removed, new). Combined with annotations and 100% schema coverage, an agent has enough to call it correctly; the remaining gap is the exact shape of the returned report.

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 meaning beyond the schema by explaining where the lock comes from ('as returned by watch or tool_card') and why last_trip exists ('keeps the map honest; 5 accepted reports earn 1 free call'). It does not clarify the last_trip fields' semantics further, which are already documented in the schema.

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 that an MCP server's tools are still the ones a person approved') and frames it with a concrete analogy ('like a lockfile'). The rug-pull framing and the per-tool outcome list make it distinguishable from siblings like tool_card, watch and changes_since.

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?

Clear trigger context: use it after approval, passing the lock you saved, to detect post-approval tool changes. It references watch and tool_card as the source of the lock and points to list_paid_tools for pricing, but it never explicitly says when not to use it or how it differs from changes_since/preflight.

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