alpha_run_stop

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

Annotations already indicate this is a mutation (readOnlyHint=false) and non-idempotent, but the description adds no additional behavioral context. It doesn't clarify side effects such as whether the run's status changes, whether the stop is permanent, or if any permissions are required. For a mutation tool, this is a significant gap beyond what annotations provide.

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 a single, well-structured sentence that front-loads the action and immediately clarifies the target. There is zero waste; every word contributes to meaning, making it highly efficient.

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?

Given the tool's simplicity (one required parameter) and the presence of an output schema, the description doesn't need to detail return values. However, it lacks essential behavioral context for a mutation: what exactly does 'persist a stop reason' do to the run? Does it mark it as stopped? Is it reversible? These gaps make it incomplete for an agent needing to anticipate consequences.

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 defines a single run_id with no description (0% coverage). The description adds the word 'existing', implying run_id must refer to a valid run, which provides some semantic context. However, it doesn't explain the format, expected source, or error behavior for invalid IDs, so it only partially compensates for the schema's lack of detail.

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 action ('Persist a fixed MCP-requested stop reason') and the target resource ('one existing run'). It distinguishes itself from sibling tools like alpha_run_status (status), alpha_run_report (report), and alpha_replay_execute (replay) by being the only stop operation, so an agent can confidently identify its purpose.

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 provides no guidance on when to use this tool versus alternatives, nor any conditions or exclusions. It does not mention that alpha_run_status or alpha_run_report might be better for checking state, or that this is the tool for halting a run. The implied usage is clear from the verb, but explicit routing is absent.

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