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

Annotations already mark readOnly, idempotent, non-destructive; the description adds the critical nuance that rows are attempts (not documents), ordered oldest first, and only the last describes current state. It also instructs to quote the authority's message, which is behavioral guidance beyond the annotations. No contradiction.

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?

Structured into clear paragraphs: purpose, usage, row semantics. Every sentence adds value, front-loads the main purpose, and provides actionable guidance. No filler or repetition.

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?

Despite having an output schema, the description conveys the conceptual return shape (attempts with authority code, message, raw request/response). It covers how to find the id, ordering, and how to interpret results. Nothing an agent needs to invoke 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 coverage is 0% and the schema only says 'invoice_id' is a string. The description explains why invoice_id is needed (rejected docs lack access key), how to obtain it (from list_invoices), and its relationship to reissue_invoice. This fully compensates for the schema gap.

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: 'Show every attempt made for one invoice and what came back.' It immediately differentiates from consult_invoice by clarifying it answers 'why was it rejected' with the authority's code, message, and raw request/response. This is unambiguous and distinguishes it from siblings.

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?

Explicitly names the scenario ('why was it rejected'), contrasts with consult_invoice, and explains that a rejected document has no access key, so invoice_id must come from list_invoices. It even parallels reissue_invoice for lookup semantics. This gives clear when-to-use and when-not-to-use guidance.

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