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

With no annotations provided, the description carries the burden of behavioral disclosure. It explains the tool's analytical approach (comparing last ten seasons, terrain spread, coldest ground rather than average) and the physical rationale. However, it doesn't disclose side effects, prerequisites beyond saving a block, or what happens if the block isn't found, though the schema covers the error case partially.

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 compact and front-loaded with the core question ('when frost arrives... and whether it is coming this week'), then adds the analytical detail and the physical rationale. Every sentence earns its place, though the final sentence about cold air drainage is explanatory rather than operational, which is slightly more than strictly necessary.

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 output schema exists and the tool is a read-style query, the description covers the key context: what data is returned (first-frost dates, spread, nightly assessment), the coldest-ground perspective, and the block reference mechanism. It doesn't mention billing/credits or the dpop_token, but the schema covers npub's billing purpose. The description is complete enough for an agent to invoke it correctly.

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 coverage is 67%, and the description adds meaningful context for the 'block' parameter by explaining how to reference a saved block (id, name, alias, unique partial name) and that blocks may overlap. The npub and dpop_token parameters are not described in the description, but the schema covers npub's purpose. The description compensates well for the block parameter's semantics.

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 answers when frost normally arrives on a specific ground and whether it is coming this week, returning first-frost dates, terrain spread, and night-by-night forecast for the coldest ground. It distinguishes itself from generic weather tools by emphasizing the coldest-ground perspective, though it doesn't explicitly name a sibling alternative.

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 implies when to use it: when you need frost timing for a specific saved block, and it explains the terrain-based reasoning (cold air drains to low ground) that justifies the coldest-ground focus. It doesn't explicitly state when not to use it or name alternatives, but the context is clear enough for an agent to select it for frost-related queries.

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