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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does this thoroughly: it states that the tool only builds text, not a QR image; that it normalizes and validates the Turkish IBAN using ISO 7064 mod-97; that non-TR IBANs and non-TRY currencies are rejected; and that it does not send money. This gives an agent a clear and accurate model of the tool's side effects and constraints.

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 front-loaded with a clear one-sentence summary and then provides necessary technical detail. There is minor redundancy between 'Text only — no PNG' and 'does not render a QR image,' but the extra context about EMV-style TLV, CRC-16/CCITT-FALSE, and validation rules is purposeful and earns its place.

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 six parameters, no annotations, and no output schema, the description is substantially complete: it covers input requirements, validation behavior, optional fields, technical format, and exclusions. The only notable gap is that it never explicitly states the return type or structure, though 'payload' and 'Text only' strongly imply a string result.

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%, so the baseline is 3. The description adds meaningful semantics beyond the schema by explaining that the amount becomes a 12-digit kuruş value, that omitting it produces a static QR where the payer enters the amount, and that explanation maps to application free field 10. This enriches the parameter meanings rather than merely repeating property descriptions.

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 and resource: 'Builds a person-to-person TR Karekod (FAST) payment payload from IBAN, name and optional TRY amount.' It also explicitly differentiates itself from rendering or money movement with 'Text only — no PNG' and 'This does not send money and does not render a QR image,' which distinguishes it from siblings like pay_epc_qr without ambiguity.

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 usage context is implied clearly: it is for Turkish FAST person-to-person QR payloads. However, the description does not explicitly say when to prefer this tool over alternatives such as pay_epc_qr, nor does it state when not to use it. The reader infers the scope from 'Turkish' and 'FAST' but receives no explicit routing guidance.

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