refill_card

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

No annotations provided, so description carries full burden. Discloses key behaviors: idempotency via UUID reuse 'to retry safely without double-charging', rejection condition 'Omitting on a Mode A card will cause the server to reject', and state constraint that modes cannot be switched mid-life. Minor gap: does not describe success response format or explicit side effects (e.g., balance update timing).

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?

Excellent structure with zero waste. Front-loaded with 'Advanced: refill...' statement. Clear visual separation of Mode A vs Mode B using headers and numbered steps. Every sentence conveys critical workflow, constraint, or API mapping information. Appropriate length for complexity (8 parameters, 2 distinct modes).

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?

Very complete for complex tool with nested objects and multi-stage workflow. Covers prerequisites (get_x402_payee_address), authorization requirements (EIP-3009 signing), and ownership constraints (same client_id). Minor gap: no output schema exists and description does not specify return value structure or success indicators, though API endpoint mapping provides partial context.

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 has 100% coverage (baseline 3). Description adds significant orchestration context: maps parameters to modes (Mode A: client_request_id; Mode B: x402_* fields), provides 3-step workflow for Mode B explaining parameter relationships ('payment_payload (signature + wallet address)'), and clarifies that x402_reference_id serves as idempotency key in Mode B despite different parameter name.

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?

Description uses specific verb 'refill' with resource 'stream card' and explicitly maps to API endpoint 'POST /payment/cards/:card_id/refill'. The 'Advanced:' prefix and detailed mode differentiation (A vs B) clearly distinguish this from sibling tool 'clawallex_refill'. The constraint 'Only cards created by this agent' further clarifies scope.

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 explicit when-to-use guidance: 'Refill mode follows the card's creation mode (cannot switch mid-life)'. Details Mode A (client_request_id) vs Mode B (EIP-3009 signing) workflows. References sibling tool 'get_x402_payee_address' as prerequisite for Mode B. Explains idempotency retry behavior for safe usage.

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