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

Although readOnlyHint=true already covers safety, the description goes well beyond that: it discloses the auth requirement, enumerates the four possible verdicts, describes the return contents ('typed hits, source kind and read date'), and clarifies edge-case semantics ('Unknown counts as no; the word safe is never used'). This is rich, non-obvious behavioral context.

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?

Every sentence earns its place: purpose, auth prerequisite, return contract, and key behavioral caveats. The core purpose is front-loaded, and there is no filler or repetition of schema details.

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?

With no output schema, the description appropriately discloses return verdicts and result contents. It covers the main invocation needs and key semantics, though it could add a bit more about how verdicts map to downstream decisions or when to prefer a sibling tool. Still, it is sufficiently complete for a well-scoped check operation.

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%, so the schema already documents subject kinds, threshold fields, and restriction formats. The description adds useful relationship guidance ('restrictions, thresholds, or both') but does not compensate for the remaining unexplained parameter aspects. It is adequate but not exceptional.

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 uses a specific verb ('Rule') and a clear resource ('one food subject against the household premise'), and names the two premise types ('restrictions, thresholds, or both'). It strongly implies a single-item check rather than a plan or venue check, though it does not explicitly name sibling tools to differentiate them.

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 gives clear context: this is for checking one food subject against household restrictions/thresholds, and it states a prerequisite (needs an API key obtainable via register). It does not explicitly say when not to use it or name alternatives like check_plan or check_venue, but the 'one food subject' phrasing provides enough contextual guidance.

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