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

With no annotations, the description carries the full burden, and it does disclose one genuinely useful behavior: on a finished call it cancels the scheduled retry rather than the call. However it omits other key traits — whether an active call is hung up or merely flagged, whether cancellation is reversible, and any permission requirements.

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 sentences, zero filler, and the primary action leads with the edge-case clarification following it. Nothing is wasted.

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 mutation tool with no annotations and no output schema, the description covers the core action and one edge case but leaves return behavior, permission requirements, and parameter meaning undocumented. Adequate but with clear gaps.

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?

The schema has 0% description coverage on two required parameters (id, workspaceId), and the description does not compensate at all — it never mentions the call identifier or workspace scoping, so an agent must infer both from the schema's UUID patterns alone.

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 (Cancel) and resource (queued or active call) with clear scope, and the second sentence pins down a non-obvious edge case. It is distinguishable from siblings like campaigns_cancel and calls_get, though it never explicitly names them.

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 versus alternatives (e.g. campaigns_cancel, or waiting for a call to finish), no prerequisites, and no statement about when cancelling is inappropriate or irreversible. Usage is only implied by the tool name and the state list.

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