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

Annotations already declare the safety profile (not read-only, not destructive, not idempotent, closed-world). The description adds genuinely useful context beyond that: the seller is notified as a side effect, and an API key is required. It does not address the non-idempotent behavior declared in annotations, which matters for retries.

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 short sentences, each earning its place: the action, the side effect, and the auth requirement, with the core action front-loaded. No filler or restatement 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?

For a mutating, non-idempotent tool with no output schema and sparse parameter documentation, the description covers the outcome and auth but omits failure behavior, whether a duplicate call is rejected, and what the buyer_wallet parameter must match. Adequate but with clear gaps.

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?

With three required parameters and only 33% schema description coverage, the schema documents just 'signature' as a Solana transaction signature. The description adds no meaning for order_id or buyer_wallet, leaving the linkage between the payment and the order, and whose wallet must be supplied, to inference.

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 gives a specific verb and resource: 'Verify a sent payment on-chain and mark the order paid.' That is far more informative than the title alone and implicitly distinguishes it from build_payment, which only constructs the payment. It stops short of explicitly naming the sibling it complements, so it is clear but not fully differentiated.

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 phrase 'a sent payment' implies this is the step that follows sending funds, giving an implied position in the order flow, but no explicit when-to-use, prerequisites, or alternatives are stated. An agent must infer that build_payment/sending must happen first.

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