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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description is consistent with them ('Read-only') while adding genuinely new behavioral facts. It discloses the null-result sentinel ({person: null}), the deliberate security property that a wrong-workspace id is indistinguishable from a missing one, and the merged-record behavior where a stale link still resolves via 'merged_into_id'. These are exactly the surprises an agent needs to know before interpreting a result.

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?

Three short sentences, zero filler, and the identity of the tool is front-loaded before edge cases. Each of the two trailing sentences covers a distinct, non-obvious behavior (null sentinel, merged records) and nothing is restated from the annotations or 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 single-parameter read with no output schema, the description covers the missing pieces an agent would otherwise have to discover at runtime: the null return, the workspace-visibility caveat, and the merged-person case. Nothing needed to call it or interpret its result correctly is absent.

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?

There is one parameter at 0% schema description coverage, so the description has to carry meaning for person_id. It says the lookup is 'by id' and that ids are visibility-scoped to the caller's workspace, which is useful, but it never says the value is an internal person id (versus a user id or external identifier) or what form a valid id takes.

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 gives a specific verb ('Read'), a specific resource ('one person by id'), and an enumeration of what the record carries (contacts, tags, consent/retention state, applications, internships). That clearly separates it from list/report siblings, but it never differentiates itself from look-alikes such as get_person, person_brief, or person_context, so it stops short of a 5.

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?

Usage is only implied: the tool takes an id, so an agent can infer it should be called when a person id is already known rather than when searching or browsing. There is no explicit when-to-use/when-not statement and no named alternative for the case where the caller only has a name or email, which is exactly the ambiguous decision this tool sits next to.

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