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

Beyond the annotations (destructive=false reading is already covered by destructiveHint=true and idempotentHint=true), the description discloses the no-effect status list, that the response carries updated run details, and — critically — that a valid x402 payment signature is required in _meta["x402/payment"]. The payment/auth prerequisite is a major behavioral fact not derivable from structured fields.

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-loads the core action and the no-op conditions, then groups usage, examples, and payment requirements cleanly. Slight waste in the two near-identical usage examples, which convey essentially the same invocation.

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?

An output schema exists so return values need not be spelled out, and the annotations already cover the destructive/idempotent profile; the description still adds the x402 payment requirement and the status no-op rule. Minor remaining gap: what happens to partially produced run results after abort is not stated.

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 100%, so both runId and gracefully are already documented in the schema, and the description adds no syntax, format, or default details for either. The example 'Gracefully abort run' hints at the gracefully flag but does not explain its semantics beyond the schema. Baseline 3 applies.

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 (Abort) and resource (Actor run) plus the qualifying state ('currently starting or running') and the inverse state where it is a no-op. An agent immediately knows what the call does and when it will have any effect, without opening the schema.

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?

Provides an explicit when-to-use rule ('stop a run that is taking too long or misconfigured') and an explicit when-it-does-nothing list (SUCCEEDED, FAILED, ABORTING, ABORTED, TIMED-OUT). Two usage examples show concrete invocations, so routing is unambiguous.

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