Stop an opencode subagent

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

No annotations are present, so the description carries the behavioral burden and does add real value: it says the call returns partial output produced so far and that IDs survive an MCP server restart. It does not state whether the abort is irreversible, whether it errors on finished agents, or any permission requirements, leaving gaps for a mutation-style tool.

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?

Three short sentences, front-loaded with the action, then the return behavior, then the edge-case note. Nothing is padded; it is appropriately sized for a one-parameter tool.

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?

With no annotations and no output schema, the description covers the core action, the partial-result return, and the restart edge case. It still omits idempotency, failure modes when the agent is already stopped, and error semantics — meaningful gaps for a termination operation.

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 coverage is 0% and agent_id is undocumented in the schema, but the description adds genuine meaning about it — that IDs minted before a server restart remain valid. That is one useful semantic detail, though it does not fully document format or validity expectations for the single parameter.

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 (abort) and resource (running opencode subagent), and clarifies it stops an in-flight subagent rather than waiting on or messaging one. It stops short of explicitly naming which sibling to use instead, so it is clear but not sibling-routing.

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 phrase 'running opencode subagent' implies the condition for use, but no alternative is named (e.g., when to use stop vs wait), and there is no guidance on what to do if the agent is not running or has already finished.

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