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

The annotations already flag destructive=true and idempotent=true, and the description adds genuinely useful behavior beyond them: partial work can still incur credits and final usage/refunds only appear after settlement. That cost-and-timing detail is exactly the kind of context annotations cannot carry. It stops short of saying whether cancellation is immediate or whether an in-flight run must finish a step first.

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 sentences, front-loaded with the action and followed by the cost caveat; nothing is padded. The opening sentence is arguably too terse to stand alone, which keeps it off a 5.

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 explained, and the annotations cover the safety profile. However, for a destructive, credit-incurring cancellation the description should identify the cancelled resource and say whether the cancellation is final or synchronous; those gaps leave the agent with an incomplete picture.

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% for all three required parameters (runId, brandId, idempotencyKey), and the description supplies no parameter information at all. The low-coverage rule requires the description to compensate, and it does not, even though brandId/runId scoping and idempotency-key semantics are non-obvious for a destructive call.

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 says 'Request cancellation' but never names the resource being cancelled. An agent must infer from the tool name that this cancels a research run rather than a post, campaign, or automation, and the sibling list contains cancel_post as a near-neighbor, so the verb+resource pairing is under-specified.

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?

There is no guidance on when to use this tool versus cancel_post or the control_* siblings, and no stated prerequisites such as requiring a prior start_research run. The agent gets no routing information beyond the name.

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