Fire an event

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

Annotations already declare readOnlyHint=false and openWorldHint=true, so the write/open-world nature is known. The description adds a useful precondition ('Requires writes to be enabled') and an audience hint ('advanced'), but says nothing about effect on state, idempotency, or failure modes.

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?

Three short sentences, front-loaded with the action, then the use case. No padding; only mild redundancy between the title and the first clause.

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 mutation tool with no output schema but with annotations, the definition covers what it does and its prerequisite, but omits return/failure behavior and any routing guidance against the many other triggering siblings. Adequate but with clear gaps.

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 100% and all three parameters (event_type, event_data, instance_id) are documented in the schema. The description adds no format, syntax, or payload guidance beyond that, so the baseline 3 applies.

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?

States a specific verb and resource: fire a custom event on the Home Assistant event bus, and flags it as advanced. It does not name a sibling alternative (e.g. ha_trigger_automation or ha_call_service), so the agent still has to infer how it differs from other triggering tools.

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?

Gives an implied use case (triggering event-based automations during testing) but no explicit when-not-to-use or named alternative. The condition selecting this over ha_trigger_automation is left to inference.

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