opn_service

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

With no annotations at all, the description carries the full burden. It does disclose one critical behavioral constraint – stop needs confirm=true – which is genuinely useful for a mutating action. But it does not say whether start/stop/restart require elevated permissions, whether restart interrupts traffic or drops connections, or what happens if the service name is unknown, leaving meaningful gaps for a state-changing 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?

Two compact sentences with no filler, and the mode-selection rule is front-loaded before the confirmation requirement. The nested parenthetical of example service names makes it slightly harder to scan, but no sentence is wasted.

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 four-parameter tool with no output schema and no annotations, the description covers the routing decision, parameter purposes, and the one safety precondition needed to call it correctly. Missing are return-value expectations and permission or failure behavior, which are minor for a simple service-control endpoint.

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%, so the description must compensate and largely does: name is the service to act on (with examples), service_id is for multi-instance services, and confirm gates stop. Only 'action' remains under-explained, since the status value is not described even though the listing behavior is implied.

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 states a specific resource (services) and both modes of operation: listing when no name is given, and start/stop/restart when a name is supplied. It gives concrete service names ("unbound", "dhcpd", "openvpn") and distinguishes single- versus multi-instance services. It stops short of a 5 because the schema's 'status' action is never named explicitly, so an agent must infer that 'list services (no name)' maps to that enum value.

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?

It clearly conditions behavior on the name parameter and adds the hard prerequisite that stop requires confirm=true, plus the multi-instance hint for service_id. That is actionable when-to-use guidance. It does not, however, point to sibling tools for related operations (e.g. opn_items or opn_overview) or state when not to use it.

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