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

Annotations already declare readOnly, idempotent, and openWorld, so the safety profile is covered. The description then adds real access-control context the annotations lack: results are limited to public records, private data requires a fresh read-only signature from the original payer, and URLs or payment vouchers are not credentials. That is meaningful added behavioral disclosure.

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?

Two sentences, no filler, and the access restriction is front-loaded after the core capability. The phrase 'held-operation next action' is dense internal jargon that costs the reader a moment, keeping it from a 5.

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?

An output schema exists and annotations cover the safety profile, so the description only needs to add access semantics — which it does. The one gap is that 'held-operation next action' is never unpacked, leaving the agent unsure what the second half of the return payload represents.

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% and invoice_id already carries a format example (inv_a1b2c3d4e5f6), so the schema does the heavy lifting. The description adds nothing about the identifier's origin or format, making the baseline 3 appropriate for a single fully-documented parameter.

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?

States a specific verb and resource: 'Read public recorded invoice status and held-operation next action.' The word 'public' scopes it against private records, and the read/write contrast with the sibling create_b2b_invoice is implicit. It does not name the sibling explicitly, so it stops short of a 5.

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 supplies a when-not condition — private records and credentials need a separate signature, and URLs/vouchers carry no read authority — which is genuine routing information. However, it frames this purely as an authorization rule rather than telling the agent when to call this tool versus create_b2b_invoice or receipt_verify, so usage remains implied.

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