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

Annotations only provide readOnlyHint=false and destructiveHint=false, so the description carries the burden of explaining behavior. It does so well by stating that the operation fails with an error rather than silently no-op'ing when gap posting is disabled, accounts don't belong to the connector, or accounts no longer resolve in QuickBooks. It stops short of describing post-success state changes, but the failure semantics are a meaningful addition.

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 description is compact and well-organized: purpose first, then requirements, then lookup instructions, then failure conditions. Every sentence earns its place, and the structure front-loads the most decision-relevant information.

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?

For a write operation that depends on external QuickBooks resolution and workspace/account scoping, the description covers prerequisites, lookup procedure, validation constraints, and failure modes. The presence of an output schema means return values are documented elsewhere, so nothing essential is missing for an agent to invoke this correctly.

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 the baseline is 3; the description adds value by explaining that bank_ledger_account_id and category_ledger_account_id must be UUIDs (not names), must be exact, and must belong to the gap's register connector. This goes beyond the terse schema descriptions and materially reduces misuse risk.

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 and resource: 'Post a well_run_register_diff gap ... into QuickBooks as a Purchase or Deposit.' This clearly identifies the action, the target system, and the record type. It also distinguishes itself from likely siblings like well_run_register_diff by framing this as the follow-up resolution step for a gap.

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 gives explicit usage prerequisites: both ledger account IDs must be exact UUIDs and must be looked up first via well_query_records scoped to the register connector, with a warning never to guess or fuzzy-match. It could add an explicit 'use this when...' contrast with well_resolve_reconciliation_task, but the lookup-first guidance and failure preconditions provide strong practical direction.

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