cancel_action_goal

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

Given no annotations, the description takes on the transparency burden. It discloses the cancellation request, the asynchronous nature of the outcome, and the return value. It also mentions version requirements. However, it does not cover edge cases like already-completed goals.

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 concise and front-loaded with the key purpose. It includes necessary details without redundancy. The structure is logical, though a slight trim could be possible without losing clarity.

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 tool with no annotations, the description covers purpose, parameters, return value, and usage conditions. It is reasonably complete, though it could mention failure modes or prerequisites for the goal to be cancellable (e.g., goal must be active).

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 0%, so the description must explain parameters. It does so effectively: action_name is described with an example, and goal_id is linked to the send_action_goal tool's return value. This adds significant meaning beyond the schema's type-only definitions.

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 clearly states the tool's purpose: 'Cancel a previously sent ROS 2 action goal.' It uses a specific verb and resource, and distinguishes itself from sibling tools like send_action_goal, which is the complementary action.

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 specifies when the tool is rejected (when ROSBRIDGE_MCP_READONLY is set) and lists requirements (rosbridge_suite with action support). It provides context for use but does not explicitly mention alternatives or when not to use it.

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