x_action_cancel

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

The description discloses the core behavior (discard) and adds the state constraint 'unexecuted prepared', which is useful context beyond the annotations. However, it does not say whether the discard is reversible, what happens to the action ID afterward, or what error occurs if the action is already executed. The annotations (readOnlyHint=false, idempotentHint=false, destructiveHint=false) are present but sparse, so the description carries some but not full behavioral burden.

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 a single, tightly worded sentence with no filler or redundancy. It front-loads the verb and scope, and every word earns its place. For a tool this simple, this level of conciseness is appropriate.

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?

Although the tool is simple (one required parameter, no output schema, no nested objects), the description leaves out a crucial piece: what the `id` refers to. It also does not mention error behavior (e.g., attempting to cancel an already-executed action) or what result the agent should expect. These gaps make the definition incomplete for reliable invocation.

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%, and the description never explains that the `id` parameter is the identifier of the prepared action to discard. The agent has to infer this from the tool name and the singular 'unexecuted prepared action'. The description should have explicitly stated something like 'id of the prepared action to discard' to compensate for the missing schema documentation.

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 uses a specific verb ('Discard') and a clear resource ('an unexecuted prepared action'), and the meaning is immediately distinct from sibling tools like x_action_execute (which would run the action) and x_action_prepare (which creates it). An agent can tell exactly what operation this performs 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?

The usage is implied: you use this when you have a prepared action that has not yet been executed and you want to cancel it. However, there is no explicit guidance on when not to use it, no mention of x_action_execute as the alternative for running it, and no stated conditions or prerequisites beyond the action being unexecuted.

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