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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so safety is covered; the description adds two things annotations cannot express: it is free of cost and it requires the read scope. That auth/cost disclosure is genuinely useful. It does not mention pagination behaviour or result ordering beyond the sort parameter, keeping it out of the top band.

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?

It is short and front-loads the resource, which is good, but the single run-on sentence spliced with semicolons and the 'Free.' fragment make it harder to parse than necessary. The scope explanation is buried mid-sentence rather than given its own clause.

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?

With an output schema present the description needn't document return shape, and annotations cover the safety profile. What remains — cost, required scope, the meaning of scope=mine, and the filter/sort model — is all present, so an agent can call this correctly without guessing.

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 baseline is 3, but the description adds meaning the schema does not: it explains that scope=mine narrows to what the account tracks plus first-degree neighbours, which is far more informative than the schema's bare 'global (default) or mine'. The phrase 'sorted and filtered' also signals that q, sort and the label filters combine.

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 states a specific resource (every person the graph holds) and what each record carries (labels, accounts, counts), which is enough to distinguish it from identity_search or identity_node on inspection. It stops short of explicitly naming which sibling to use for query-type lookups, so differentiation is implicit rather than stated.

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?

'scope mine is what this account tracks and the people one edge from them' is real guidance about which scope to pick, but it only addresses one of six parameters. There is no statement of when to prefer this over identity_search, identity_library, or identity_tracked, leaving the list-vs-search decision to inference.

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