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

With no annotations provided, the description fully covers behavioral traits: returns 409 Conflict for terminal states, requires the creator identity to cancel, returns task_id and status, states cost is free, and gives typical latency. This is comprehensive and goes beyond basic mutation semantics.

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 well-structured with clear sections for action, usage, inputs, returns, cost, and latency. Each section earns its place, though cost and latency could be considered optional; however, they do not bloat the text significantly.

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?

The tool has one parameter and no output schema, and the description covers the mutation, conflict behavior, authorization, return values, cost, and latency. It provides all necessary context for an agent to decide when to use it and what to expect.

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 input schema has no description for task_id (0% coverage), but the description compensates by specifying it is a path parameter, required, and a 26-char ULID. This fully resolves the parameter's meaning and format, exceeding what the schema alone provides.

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 function: 'Marks the task as `cancelled`', with a specific verb and resource. It also mentions the conflict on terminal states, but does not explicitly differentiate from sibling tools like get_task or stream_task, so it falls short of a 5.

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 includes explicit 'Use this tool when' and 'Do NOT use this tool when' sections, giving clear invocation scenarios and an exclusion (already complete). However, it does not name alternative tools for other scenarios, so it misses the 'alternatives' component for a 5.

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