set_signal

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

With no annotations, the description fully discloses side effects: 'Writes to JMRI,' case-sensitivity, and lack of local validation. It also explains the meaning of 'confirmed' false, providing transparent feedback behavior beyond the raw action.

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?

Every sentence serves a purpose: purpose, parameter details, usage guidance, side-effect disclosure, and return interpretation. The structure with 'Args:' and a note is clean and front-loaded, with no filler.

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?

Despite no output schema, the description explains what is reported (observed aspect) and the meaning of the confirmed flag. It also covers prerequisites, alternatives, and edge cases (unlit/off), making the tool sufficiently complete for correct invocation.

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 has zero descriptions, but the description richly annotates both parameters: name (system/user/fragment, case-insensitive) and aspect (examples, case-sensitivity, no validation, special darkening values, and referral to list_signal_aspects). This fully compensates for the schema's bareness.

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 opens with 'Set a signal mast's aspect, and report the aspect actually observed,' which uses a specific verb and resource. It clearly distinguishes from siblings like signal_off (darkening) and list_signal_aspects (reading aspects) by mentioning them as alternatives.

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?

Explicit guidance is provided: call list_signal_aspects first if unsure of spelling/case, and prefer signal_off for darkening. This directly tells the agent when to use this tool versus alternatives, avoiding guesswork.

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