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

Annotations already declare idempotentHint=true, so 'Repeated calls are idempotent' is largely redundant. The description does add value the annotations lack: the once-per-local-day frequency cap, the echoesReceived counter semantics, and the instruction to relay humanMessage, which are genuine behavioral details.

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 five-sentence block is front-loaded with the frequency constraint, which is good, but several sentences are subject-less fragments ('Light once per local day', 'Use auto or one owned target') that read like notes rather than a coherent instruction.

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?

With no output schema and no annotations covering response shape, the description should explain the interaction model. It gestures at response fields (echoesReceived, humanMessage) but omits locale, leaves target selection ambiguous, and never clarifies what the call actually produces.

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 carries full burden and mostly fails. It references 'auto' and an 'owned target' but never disambiguates whether the target is wishId or shrineId, and the locale parameter is never mentioned at all.

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 opening sentence gives a specific verb (light) tied to the resource named in the tool, so an agent can infer this is a once-daily ritual action. However, it never states what 'lighting incense' accomplishes or how it differs from siblings like draw_oracle or make_wish, leaving purpose only partially resolved.

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?

It gives one concrete usage rule – 'Light once per local day' – and hints at target selection with 'Use auto or one owned target.' But it never names an alternative tool or explains when to prefer auto versus an explicit target, so routing guidance is only implied.

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