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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable context beyond annotations: it is derived from a daily external re-audit, an event exists only when a prior snapshot exists, and the tool is free. It does not contradict any annotation.

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 every sentence earns its place: it names the tool's purpose, lists concrete drift types, routes to the sibling alternative, explains the data source, and states cost. The key differentiator ('what CHANGED') is front-loaded in the title and first line.

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 2-parameter, fully-optional-parameter tool with rich annotations, this is nearly complete: the agent knows what events are detected, how the tool relates to siblings, and why snapshots matter. It lacks an explicit description of the response shape, which would be moderately helpful since there is no output schema.

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. The description reinforces that packages are npm package names and that users should pass their own dependency list, but it adds no new parameter semantics beyond what the schema already documents. The 'omit for the whole ecosystem feed' guidance is already in the schema description.

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 names the tool as 'the rug pull check' and explicitly states it answers what CHANGED after adoption, with concrete examples (install script added, ownership swapped, repository removed, unpublished, provenance lost). It clearly distinguishes itself from the sibling mcp_check_server, which checks current safety rather than drift.

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 contrasts this tool with mcp_check_server ('answers whether a package is safe TODAY; this answers what CHANGED after it was adopted'), giving the agent a clear selection rule. It also tells the user to pass their own dependency list to check it in one call, making the intended invocation flow explicit.

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