ha_call_service

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

With no annotations, the description must disclose behavioral traits. It mentions calling a service but omits side effects, permission requirements, rate limits, or failure modes. The examples suggest mutation (turn on, lock, send) but no caution is given.

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 a single sentence with examples, which is concise and front-loaded. It earns its place without fluff, though a slightly more structured format could improve clarity.

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 tool's complexity (4 parameters, nested objects, mutation potential, no output schema), the description is too minimal. It lacks information on service discovery, error handling, and return values, making it insufficient for an agent to use confidently.

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?

All parameters are described in the input schema (100% coverage). The description adds examples of service data, but these are generic and add little beyond the schema. Baseline 3 is appropriate as the description does not compensate beyond schema coverage.

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 the tool calls a Home Assistant service, with good examples. However, among many sibling tools like ha_set_state, ha_fire_event, and ha_render_template, it doesn't distinguish what qualifies as a 'service' versus other actions.

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 provides no guidance on when to use this tool versus siblings. It does not mention when not to use it, prerequisites, or alternatives, leaving the agent to infer from the name and examples alone.

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