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

The two-phase confirm gate is the key behavioral trait and the description surfaces it, reinforcing rather than contradicting the readOnlyHint=false annotation. However, the most decision-relevant behavior is unstated: all five settings params are optional and additionalProperties is false, yet it never says whether omitted fields are preserved (merge) or reset (replace) — a costly ambiguity for a mutation tool with no destructiveHint.

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?

Two clauses, no filler, and the operation is front-loaded ahead of the parenthetical confirm caveat. The confirm-gating note is placed exactly where a caller needs it before invoking.

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?

Given a six-parameter mutation tool, no output schema, and near-zero schema description coverage, the definition should do more — particularly on merge-vs-overwrite semantics and accepted value formats. What is there is accurate and the confirm gate is covered, so it is viable but with clear gaps.

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 only 17% (only confirm is documented), so the description must carry the load — and it does map its field list onto all five settings parameters, including the useful hint that preferredUnits is metric/imperial. It stops short of constraining values: the 3-character currency code rule and the kg/lbs enum for preferredWeightUnit are never mentioned, and the units-vs-weight-unit distinction is only loosely signposted.

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 opens with a specific verb+resource combination ("Set the coach's ... localization") and enumerates exactly which settings are in scope: language, currency, units, timezone, weight unit. An agent can distinguish it from adjacent update_my_* tools by the field list, though no sibling is named explicitly.

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 implied by "Set the coach's ..." — this is for the caller's own profile preferences, not another member's. But there is no when-not guidance and no pointer to alternatives such as update_my_contact or update_my_professional, so the agent must infer the boundary.

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