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

Beyond annotations, it discloses the mutation guardrail: no write until confirmWrite:true after explicit confirmation, first call returns confirmation_required with a preview, and confirmation is scoped to the selected counterparty. This is exactly the behavioral context needed for a destructive write tool.

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 seven dense, load-bearing sentences: purpose first, then token requirements, then confirmation behavior. No filler, no repetition of schema properties, and every sentence adds safety-relevant guidance.

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?

The description covers the highest-risk aspects completely: token validity, preview, explicit confirmation, counterparty scoping, and preflight caveat. It does not describe the return shape after confirmWrite or the remaining field semantics, but the transaction flow is the main hazard and is well specified.

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?

It adds meaningful semantics for routeToken, confirmWrite, and confirmCounterpartyExplicit, but those are also documented in the schema. With only 29% schema coverage, many required fields such as acCode, procDate, bookTranTypeId, and analysisCategoryId are left to name-based inference, so the description only partially compensates.

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 clear action ('Creates a purchase') and the specific mode ('using the company's generated-reference configuration'), which distinguishes it from brc_create_purchase without naming it. It does not explicitly call out the sibling alternative, so it stops short of full differentiation.

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?

It provides strong operational context: a valid routeToken for the matching workflow, token validity scope, and the confirmWrite two-step process. It also explicitly excludes shortcuts ('does not bypass preview or explicit-confirmation', 'Passing preflight is not confirmation'), but it does not state when to pick this tool over the plain purchase or other create variants.

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