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

Goes well beyond the read-only/non-destructive annotations: it discloses the matching priority order, the invoice-window constraint, the exact return semantics ('names what is left over in both directions: invoices nobody paid, money nobody invoiced, invoices paid twice'), and dedup behavior ('a duplicate is counted once, never twice'). It also flags a key limitation about payer identity.

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?

Four short sentences, front-loaded with the matching rule, followed by output semantics and a caveat. No redundant restatement of the title or schema, and every sentence carries information.

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, the description takes on the burden of describing results and does so precisely by enumerating the three leftover categories and the dedup rule. Combined with the caveat about payer attribution, an agent has everything needed to call and interpret it.

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 meaning the schema does not: it explains that memo is the primary join key and that amount plus asset are compared inside the invoice creation window. This tells the agent how the two arrays are actually consumed together.

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 ('Match invoices to stablecoin transfers') plus the exact matching algorithm (memo first, then amount/asset within the invoice window). Nothing in the sibling set (reserve_report, resolve_report, verify_receipt, audit_spend) overlaps with this reconciliation job, so the purpose is unambiguous.

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?

Provides an explicit exclusion: 'Do NOT use as proof of who the payer was,' which steers the agent away from an attribution misuse. It does not name alternative tools for attribution or explain prerequisites, so it falls short of a full when/when-not routing guide.

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