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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses the status precondition and the failure outcome for published rows, but says nothing about side effects on the Nova-side scheduling, whether cancellation is reversible, or how partial failures behave.

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 short sentences with the core purpose front-loaded, which is good. The trailing 'Uses publisher_pid in the URL path (same as schedule)' sentence is internal implementation trivia that does not help an agent invoke the tool and risks confusion with a different parameter name.

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?

There is no output schema and no annotations, so the description must stand alone for a mutation tool. It covers preconditions and the primary failure case, but omits what the caller receives on success, what happens to already-queued Nova posts, and whether a cancelled entry can be rescheduled.

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 only 50%: history_id is undocumented in the schema, and the description never explains its format or how to obtain it, instead mentioning 'publisher_pid in the URL path', which is an internal routing detail irrelevant to the caller's argument. The remaining sentence does not compensate for the coverage gap.

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?

Opens with a specific verb+resource ('Cancel a scheduled or pending publish') and narrows scope with '(Nova + local history)', which separates it from cancel_project_asset and delete_* siblings. It never explicitly contrasts with unschedule_calendar_row, the closest sibling alternative, so sibling differentiation is incomplete.

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?

The description gives genuine eligibility rules ('Only works when history status is pending, publishing, or scheduled; published rows return not cancellable'), which tells the agent when the call will succeed. However, it offers no guidance on when to choose cancel_publishing_history over unschedule_calendar_row or list_publishing_history, so the alternative-selection guidance is only implied.

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