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

Annotations only declare readOnlyHint, and the description adds substantially: the enumerated return facts (authorizationSavedAt, snapshot status/time/error, refresh eligibility, tokenRotationVersion, tokenRotationAudit fields) and an explicit disclosure that raw credentials, Vault ids, secret ARNs, and rotation grant metadata are never returned. That sanitization guarantee is genuinely useful behavioral context beyond the annotation bar.

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?

The front-loaded first sentence is good, but the remainder drifts into instructions for how the agent should phrase a reconnection conclusion ('state the returned ... separately from ...') rather than tool semantics, and the 'separate facts' idea is restated three times. Much of the text does not help an agent decide or invoke, violating the every-sentence-earns-its-place bar.

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 no output schema, the description carries the burden of describing returns and it does so thoroughly, including the distinct timestamps and the negative space of what is never returned. The only gap is the single input parameter, whose provenance and format are unaddressed.

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 0%, so brokerCredentialId is undocumented in the schema, but the description compensates partially by constraining it to 'one saved broker credential owned by the authenticated user.' It says nothing about format (UUID) or how to obtain the id, so the compensation is only partial.

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 opening sentence gives a specific verb and resource ('Read-only token refresh status for one saved broker credential') plus an ownership scope. The second sentence situates it in the Schwab/Tradier OAuth snapshot flow, which implicitly separates it from siblings like test_schwab_broker_connection, but 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?

'Use this after Schwab or Tradier OAuth snapshot runs to verify whether Node persisted rotated token material' gives a clear triggering context. There are no explicit exclusions or named alternatives (e.g., nothing says use test_schwab_broker_connection instead when you want a liveness check), so it stops short of full routing guidance.

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