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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely useful behavioral context beyond annotations: the payload is an array (verified live, test account returned array[0]) and flags the singular-method/plural-payload trap. That is the kind of detail that prevents downstream parsing errors.

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 what the tool returns, then the endpoint and the array caveat. Three sentences, all contributing. The bolded emphasis on ARRAY is well-placed, though the endpoint path reference is arguably noise given there are no args.

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?

No output schema exists, so the description correctly carries the return-value burden, specifying PersonalRecords is a PersonalRecord[] with one row per record type. Combined with the array warning, an agent has enough to call and parse it, though the phantom {displayName} path leaves a small ambiguity.

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?

With zero parameters the baseline is 4, but the description references a `{displayName}` path segment while the schema declares no parameters and says "no args." This slight mismatch between the documented endpoint and the actual schema could confuse an agent about whether input is required, warranting a nudge down.

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: retrieves "the account's personal records, one row per record type." This distinguishes it from siblings like get_activities or get_goals since personal records are a distinct resource. It does not explicitly name an alternative, so it falls 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?

The description never states when to use or avoid this tool. No prerequisites, no alternatives, no context about why an agent would call it over a general stats tool. It is implied only by the resource name.

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