control_service

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

With no annotations provided, the description carries the full burden. It discloses that system scope may require authorization (polkit) and that it returns rc and new ActiveState. It could additionally clarify that enable/disable affect startup state while start/stop affect current runtime, but overall it is fairly transparent.

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 concise (3 sentences) and front-loaded with the action list. It efficiently communicates the core functionality, constraints, and return value. A slightly more structured format (e.g., bullet points for actions) could improve readability, but it is already 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 absence of annotations and zero schema coverage, the description provides the essential information: actions, authorization requirements, and return format. However, it does not specify the exact range for the 'scope' parameter (system vs user) and does not relate to sibling tools like get_service_status for pre-checking. The existence of an output schema is noted but not detailed.

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. While it lists the possible actions in the description, it does not describe the 'service' or 'scope' parameters with sufficient detail (e.g., valid values, formatting). This leaves the agent with incomplete information.

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 it performs actions on systemd units (start/stop/restart/reload/enable/disable), which distinguishes it from sibling tools like get_service_status that only retrieve status.

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 mentions that the tool is gated by SYSCONTROL_ALLOW_ACTIONS and may prompt for authentication via polkit, providing important context for when and how to use it. However, it does not explicitly mention when not to use it or suggest alternatives like get_service_status for checking status before action.

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