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

Adds substantial context beyond the annotations (readOnlyHint=false, openWorldHint=true, idempotentHint=true): an async result pattern with ~2-minute latency, a lookup_id handoff, coverage back to ~1960, a disclaimer that nothing returned is a property determination, and a quota of 10 free lookups per month per key. No contradiction with the annotations.

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?

Front-loaded with the action and the follow-up handoff, then coverage, disclaimer, and quota. Every sentence carries information, though the 'Records, not opinions' framing is slightly editorial and could be tighter.

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 two-parameter submission tool with no output schema, the description supplies everything the agent needs: async behavior, the returned lookup_id, the follow-up tool, latency, data coverage, and the per-key quota. No output schema is needed given the lookup_id handoff is explained.

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% — address format (with a full example) and date format (YYYY-MM-DD) are already documented in the schema. The description only restates 'one U.S. street address and date' and adds no syntax or constraint beyond that, so the baseline 3 is correct.

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+resource ('Start a weather-records lookup') scoped to 'one U.S. street address and date', and explicitly names the sibling get_lookup as the follow-up. An agent can distinguish it from get_lookup without opening either schema.

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 clear lifecycle context: this call returns a lookup_id, results are ready in about two minutes, and the agent should then 'call get_lookup with it'. That effectively routes between the two siblings, though it never states when NOT to use this tool (e.g., caching or reusing an existing lookup).

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