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

Annotations already disclose mutation, non-idempotence, open-world behavior, and non-destructiveness; the description adds the forecast horizon and free-tier limit. It does not explain the "start" lifecycle, such as whether a job must be polled via get_job_result, or auth/rate details beyond pricing. This is useful but incomplete for a non-idempotent generator.

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?

Two short sentences, front-loaded with the action and forecast horizon, plus a compact pricing note. No filler or repetition; every clause contributes useful scoping.

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 an open-world, non-idempotent forecast generator with an output schema, the description gives enough to initiate the call and understand the horizon. It omits the job/result retrieval path and most parameter semantics, leaving gaps that matter for correct downstream use.

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 parameter meaning, but it only clarifies `days` as 1-15 days with up to 7 free. It says nothing about `lat`, `lon`, `api_key`, or `location_name`, leaving most parameters documented only by name/default.

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 ("Start") and resource ("forecast EPW") and gives the 1-15 day horizon plus example use cases, so the agent can distinguish it from generic EPW/TMY generation. It does not explicitly contrast with siblings such as generate_epw or generate_future_climate, which keeps it from a 5.

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 use cases (operational sims, MPC, demand response) imply when a near-term forecast is appropriate, and the 1-15 day range constrains use. It never explicitly says when to choose generate_epw, generate_future_climate, or generate_tmy instead, nor does it state exclusions.

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