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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered. The description's "Returns L/week and watering frequency" only duplicates the existing output schema, adding little behavioral insight beyond 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?

Four short, front-loaded sentences with no filler; the purpose leads and details follow. The only slightly wasteful part is restating return values already covered by the output schema.

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 read-only calculator with a full output schema and annotated safety profile, the description is nearly sufficient and even adds a useful cross-reference to list_bundles. The input paraphrase mismatch (climate vs season, plant mix vs plant_type) is the main remaining gap.

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 100%, so the baseline is 3, but the description's paraphrase is inaccurate: it names "climate" where the schema parameter is season, and "plant mix" where the schema has a singular plant_type enum. Renaming parameters risks misleading the agent rather than clarifying them, dropping it below the schema-only baseline.

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 (compute) and resource (weekly water needs for a garden by area and plant type), which clearly separates it from garden-adjacent siblings like calculate_garden_soil or calculate_garden_sunlight_hours. The core purpose is unambiguous, though it doesn't explicitly name which sibling would be used instead.

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?

"Use for irrigation planning" implies a usage context but gives no when-not guidance, prerequisites, or explicit alternatives among the many garden/water calculators. The mention of list_bundles is a directory pointer, not selection guidance.

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