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

Annotations already cover read-only, idempotent and non-destructive, so the bar is lower; the description still adds real value by disclosing the return shape ('each kind with its count and ids') and that the call is free. It stops short of stating match strictness (exact vs. partial), result caps, or what happens with zero hits, which for a read with no output schema would be useful.

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 verb and scope, and each sentence carries distinct information (purpose, GDPR use case, return shape, alternatives, cost). The long enumeration of areas is partly redundant with 'across every area' and 'with their chats and CRM history', which is the only wasted space.

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-optional-param lookup with annotations covering the safety profile and no output schema, the description covers purpose, trigger, return contents, cost and sibling routing. Nothing an agent needs in order to choose and call this correctly is missing.

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% and both properties already document their formats, so baseline is 3. The description adds one meaningful nuance the schema does not — that either an email or a phone can identify the person — but does not say whether both may be supplied together or how they are combined.

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 ('Every record this account holds about one person') with an explicit scope ('across every area') and an explicit matching key (email or phone). It also names the two closest siblings, account_export_person and account_erase_person, so an agent can differentiate without opening any schema.

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 a concrete triggering scenario ('For a person who asks what the business keeps about them (GDPR Art. 15)') and routes the adjacent intents away: export for a copy, erase for deletion. When-to-use and the alternatives are both spelled out, not inferred.

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