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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description still adds real value by disclosing provenance: the business's own site, its Business Profile, dated fact history, CrawlCheck scans of other sites, and for unknown numbers a web search plus YellowPages reverse lookup. It omits cost/latency of that external lookup, keeping it from a 5.

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 precondition and the core 'one signed verdict per field' promise before the dense per-field verdict and source enumeration. It is long and a single block, but each clause carries operative detail rather than filler.

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?

There is no output schema, so the description carries the return-value burden, and it does so by enumerating the possible verdicts per field (matches, former_value, not_this_business, not_published, nothing_declared, open/closed, declared). Inputs, trigger, and output semantics are all covered for this read-only tool.

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 enum documents the field parameter, but the description goes further by listing the verdict vocabulary per field type and clarifying how a value must be shaped (10-digit number, a week like Mo-Fr 08:00-17:00 vs a moment like Sa 10:00, a place name). This meaningfully exceeds the schema's brief value hints.

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 and resource: it produces one signed verdict for a named business field (phone/address/hours/service_area), which is far more than a restatement of the name. It is distinguishable from the fix_*/resolve_* siblings by its read-only verification purpose, though it never names an alternative tool to contrast against.

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?

"Call before using a phone number, address, opening hours or service area you hold for a business" gives a clear triggering condition and scope. It stops short of exclusions or naming sibling tools, but the when-to-use context is unambiguous.

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