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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds meaningful behavioral context beyond that: it explains the cancelled true/false return semantics and explicitly states that candidates and results produced before the stop remain saved.

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 three tight sentences, front-loaded with the core action and followed by return semantics and data-preservation behavior. Every sentence adds useful information without repetition.

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 simple one-parameter destructive tool with no output schema, the description covers the action, return semantics, and preservation of prior results. It does not address error cases or ownership validation, but it is otherwise complete enough to call correctly.

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% for the single required sessionId parameter, so the description must carry the semantic burden. It partially compensates by describing the target as an 'owned sourcing session' with an 'active turn,' but it does not name the parameter or explain its constraints explicitly.

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 and resource: 'Cancel the active turn of an owned sourcing session.' That is clear and distinguishable from most siblings, but it does not explicitly contrast itself with sibling tools such as sourcing_continue or sourcing_start.

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?

Usage is implied by 'Cancel the active turn' and the 'owned sourcing session' qualifier, but the description gives no explicit when-to-use guidance, prerequisites, or named alternatives. An agent can infer the purpose, but routing versus sibling tools is left mostly to the tool name.

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