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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description doesn't need to restate safety. The description adds useful behavioral context: it is a deterministic pipeline, requires one payment, and emits a signed receipt covering the whole batch. That goes beyond the annotations and informs the agent about side effects and cost semantics. It doesn't detail failure behavior or whether the call fails as a whole, but the added context is strong.

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 information-dense and front-loaded with 'HIGH-THROUGHPUT DETERMINISTIC PIPELINE', immediately setting the tool apart. Every sentence adds value: what it runs, how many, the payment model, why it's useful. Slightly shouting-heavy capitalization costs a little polish, but the content is well-ordered and not bloated.

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 tool with a rich input schema, output schema, and clear annotations, the description captures the essential operational context: batching, payment, receipt, and target use case. It lacks an explicit statement about what happens on partial failures (e.g., does one invalid item fail the entire batch?) and doesn't mention its relationship to autonomous_commercial_pipeline, but these are relatively minor given the schema and annotation coverage.

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%: the single 'items' parameter is documented with type, min/max, and nested properties. The description adds the batching context ('up to 50', 'one paid call') which maps to the maxItems constraint, but it doesn't repeat or enhance the per-item field semantics. Baseline 3 is appropriate because the schema does the heavy lifting.

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 uses a specific verb ('Run') and resource ('up to 50 business identifier checks') and clearly differentiates this from the single-check sibling tools by emphasizing the batch pipeline ('ONE paid call', 'one voucher, one settlement, one signed XDR-1 receipt'). An agent can immediately distinguish batch_validate from its siblings like iban_check or vat_mod97_check without opening the schema.

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 states a clear primary use case ('essential for autonomous batch invoice processing') and implies when to use the batch tool over individual checks (10x cheaper per item, up to 50 checks in one paid call). It does not explicitly list exclusions (e.g., 'use single-check tools for fewer than N items'), but the context is strong enough to route an agent correctly.

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