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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral value beyond that: output is Markdown, computed from that city's own frost dates, and months with nothing to sow explicitly return a pointer to the next sowing month instead of an empty result.

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 sentences, front-loaded with what the tool produces and backed by the frost-date rationale and the empty-month edge case. No filler wording and nothing redundant.

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 read-only lookup with no output schema, the description covers source of truth (frost dates), format (Markdown), and the degenerate case. The only gap is that it does not spell out the shape of the Markdown sections or how frost dates are resolved for ambiguous city names.

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%, so both parameters are already documented, including the find_city slug convention and accepted month formats. The description contributes only the insight that the city drives the frost-date calculation; it adds no format or validation detail beyond the schema, 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?

The description names the concrete output categories (start indoors, sow outdoors, plant out) scoped to a city and month, and states the output format is Markdown. It is specific enough to distinguish this from get_plant, which covers a single plant rather than a monthly task list, though it does not name a sibling explicitly.

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?

Usage is implied (ask this when you want seasonal sowing tasks for a place), but there is no explicit when-to-use vs. when-not guidance and no named alternative for related questions like city lookup or plant detail. The fallback behavior for empty months is a useful hint, but it is about output, not tool selection.

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