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

Beyond destructiveHint=true, the description discloses the actual side effects: unasked answers are dropped, and one answer already in flight may still arrive and be stored. That partial-cancellation semantics is exactly the kind of consequence an agent cannot infer from annotations.

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?

Three tight sentences, side effects front-loaded after the verb, and the provenance hint last. Nothing is padding.

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 two-parameter destructive tool with no output schema, the definition covers what it does, where the id comes from, and the non-obvious consequences of cancelling. An agent has everything needed to call it and to set expectations about results.

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% and the schema already documents runId with the same provenance list, so the description repeats rather than adds. projectId is not mentioned in the description at all. Baseline 3 is appropriate when the schema carries the parameter burden.

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?

"Stop a running scan of a site" is a specific verb plus resource, and it implicitly contrasts with the start_scan sibling. It stops short of explicitly naming start_scan as the inverse operation, but the intent is unambiguous.

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 clearly frames the situation (a scan is currently running) and tells the agent where the runId comes from — start_scan, get_live_scan or list_scans. It does not state what to do if the scan has already finished or how to confirm cancellation, which keeps it from a 5.

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