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

The annotations already flag the operation as non-read-only and destructive-ish, so the description's job is to explain the real side effect, which it does well: one people credit per matched person, one property credit per included property, and no charge on a miss. What is left unexplained is why destructiveHint is set on what reads as an enrichment lookup, and whether results are cached or metered on repeat calls.

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 sentences, front-loaded with the primary action and input, then return shape, then prerequisites and cost. No sentence is redundant and none restates the title verbatim.

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?

Despite having no output schema and a nested location parameter, the description covers inputs, what the response contains, the optional property expansion, and the billing behavior. An agent has everything needed to decide to call it and to predict the charge.

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 all four parameters including the nested location object are documented structurally, which sets the baseline at 3. The description reinforces the email requirement and the credit consequence of include_properties, but adds nothing about the 'fields' whitelist or how location narrows a match.

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 ('looks up a person by email address'), names the required key, and enumerates what comes back (name, contact info, demographics, optional properties). Against siblings like dealmachine_enrich_name, dealmachine_enrich_phone, and dealmachine_enrich_address, the lookup key alone makes the distinction unambiguous.

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?

Gives clear operating context: a connected paid DealMachine account is required, and the cost model is spelled out per match. It does not explicitly route the agent away from sibling lookups when the identifier is a phone or name rather than an email, so the when-not guidance is only implied.

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