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

With no annotations, the description carries the full disclosure burden and does so well: it defines timestamp semantics (paid_at/period use payout time; accepted_at is final acceptance time or null), states exclusion rules, and warns that CSV cells resembling formulas get a leading single quote. That last detail is exactly the kind of non-obvious behavior an agent could not infer elsewhere.

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?

Three tight sentences, front-loaded with the core purpose, then behavior, then the edge-case formatting note. Every sentence carries information; no filler or repetition of the title.

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?

With no output schema and no annotations, the description must supply return-shape and safety context, and it covers the key parts: line items, per-line verification receipt, timestamp fields, exclusions, and CSV escaping. Minor gaps remain (e.g., pagination or ordering behavior, whether it is read-only by nature), but nothing critical is missing for a correctly-scoped read.

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, but the description adds genuine meaning: it clarifies that the period and paid_at are interpreted against payout time, which is not stated in the from/to schema text. It does not, however, restate or elaborate the under-366-day constraint or the organization_id/agent_key requirements beyond what the schema says.

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 ('Return an account's recorded supplier transfers for a period, each line with its machine-verification receipt'), which is far more precise than the title. It distinguishes itself from adjacent tools like receipt/settlement through the 'recorded supplier transfers' framing, though it never names an alternative explicitly.

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 establishes scope by exclusion ('Prepayments awaiting payout and internal settlements without a transfer are excluded'), which implicitly tells the agent when this tool is the right fit. However, it never names a sibling alternative or states a prerequisite/context condition for choosing this tool over e.g. procurement_contract_run or settlement.

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