service_list

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

readOnlyHint=true already tells the agent this is a safe read, and the description adds value beyond that by declaring the state domain (RUNNING/STOPPED) and the fields returned, which matters because there is no output schema. It stops short of covering auth, pagination, or error behavior, but the bar is lower with annotations present.

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?

Front-loaded with the [READ] marker and the core purpose, followed by a short Args block. Efficient with no filler, though the bracketed marker and Args formatting are slightly more verbose than strictly necessary.

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 read-only one-parameter list tool with no output schema, the description supplies the missing pieces: the read nature, the returned fields, and the parameter's default behavior. Only minor gaps remain (no mention of service_restart as the mutation counterpart, no sort/filter notes).

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 carry the single parameter, and it does: target is the TrueNAS target name from config and can be omitted in favor of the default. That is exactly the semantics an agent needs for a nullable, defaulted argument.

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 gives a specific verb+resource ("List system services") and even enumerates the returned fields (name, state, enable), which is more than most list tools offer. It does not explicitly name the sibling alternative (service_restart), so it falls short of the top mark for sibling differentiation.

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 only usage guidance is on the target argument ("omit to use the default"), which is really parameter help rather than when-to-use guidance. There is no statement about when to pick this over service_restart or other *_list tools, so usage is only implied by the verb.

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