query_history_ask_cancel

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

Annotations only supply readOnlyHint=true, which is arguably in tension with a 'stop/cancel' verb (though cancelling a stream need not mutate stored data). The description says nothing about what happens to the pending answer, whether it is discarded or partially returned, or whether the cancel is idempotent, so the behavioral burden is largely unmet.

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?

One short, front-loaded sentence with no filler; the action and scope lead the sentence. It is efficient, though the brevity comes at the cost of the missing detail noted elsewhere.

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 cancellation tool with an undocumented required key, no output schema, and only a readOnlyHint annotation, the description leaves the agent guessing about target identity and post-cancel behavior. It is not sufficient on its own.

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 single required parameter 'key' has 0% schema description coverage and the description never explains it — the agent cannot tell whether it is a query ID, an answer ID, or a session key. With low coverage the description was expected to compensate and does not.

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 (stop) and a specific object (Claude's in-app answer for one query), which is more precise than a bare name restatement. It does not differentiate itself from the near-identical sibling sql_editor_ask_cancel, nor from query_history_ask/query_history_answer, so an agent must infer the pairing from the name alone.

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?

No when-to-use guidance at all: it does not say to call this only while an answer is still generating, nor that it is the query-history counterpart of sql_editor_ask_cancel. The agent gets no condition that selects this tool over its siblings.

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