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

Annotations already declare readOnly, non-destructive, closed-world, so the bar is lower. The description still adds genuine value: it says the call is free and requires read scope, and it enumerates what the response contains (evidence attached to edges, vendor/cost/timestamp of pulls, last-pulled times, held date ranges, metric history). That's more than the annotations or the output schema's existence alone conveys.

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's front-loaded with "One node in full" and then spends its words on the return contents. The long enumerated clause is dense but each item earns its place, and the two trailing sentences ("Free. Needs the read scope.") are clipped and efficient.

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 one required param, full schema coverage, an output schema, and read-only annotations, the description fills the remaining gaps an agent would care about: cost, required scope, and the kinds of data returned. It stops short of covering error behavior or what happens for a missing id, but nothing essential to invoke it 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 description coverage is 100% and the single id parameter is documented in detail, including the person:/account:/organization:/asset: formats. The description itself says nothing about the id, so baseline 3 is right – the schema does the work here.

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?

"One node in full" states a specific verb and resource, and the list of contents (fields, edges with evidence, pulls, expansions, date ranges, metric history) makes the scope concrete. It doesn't explicitly distinguish itself from siblings like identity_search or identity_expand, though the schema description mentions identity_search finds ids.

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?

"Free. Needs the read scope" gives cost and auth context, which implies it's safe to use liberally. But there's no explicit statement of when to use this versus identity_expand, identity_similar, or identity_search – the agent has to infer that from the name.

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