complete_paid_rail_run_with_callbackComplete paid run, build callback envelope, optionally deliver callback_url, and store callback proof.
| Name | Required | Description | Default |
|---|---|---|---|
| rail_key | No | ||
| callback_url | No | ||
| idempotency_key | No | ||
| payment_reference | No |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses multiple mutative side effects: completing the run, building a callback envelope, optionally delivering to callback_url, and storing callback proof. This adds meaningful context beyond the readOnlyHint=false annotation, though it omits prerequisites and failure behavior.
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 a single concise sentence that front-loads the primary action and enumerates subsequent steps. There is no redundancy or filler, making it well-structured and efficient.
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?
Given the tool has four parameters, no output schema, and only a readOnlyHint annotation, the description omits critical context such as return values, prerequisites, and idempotency semantics. The action is described, but the overall contract is incomplete for an agent to invoke it confidently.
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 0%, so the description must compensate. It only explicitly mentions 'callback_url' and alludes to payment via 'paid', but does not explain 'rail_key', 'idempotency_key', or 'payment_reference'. The schema provides names and an enum, but the description adds little additional meaning.
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 ('Complete') and resource ('paid run') and outlines sub-actions (build callback envelope, deliver, store proof), making the core purpose clear. However, it does not explicitly distinguish itself from sibling tools like 'complete_agent_self_serve_paid_rail_run' or 'build_a2a_callback_envelope', so it falls short of a 5.
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 provides no guidance on when to use this tool versus alternatives. It does not state 'use when...' or contrast with sibling tools such as 'build_a2a_callback_envelope' or 'complete_agent_self_serve_paid_rail_run', leaving the agent without sufficient decision context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
With 89 tools, there is extensive overlap. For example, multiple tools handle completing paid rail runs (complete_agent_self_serve_paid_rail_run, complete_paid_rail_run_with_callback, run_stripe_receipt_completion) and several verify receipts (verify_receipt, verify_managed_receipt_signature, verify_signature_by_version). Distinguishing between these without deep inspection is nearly impossible.
Most tool names follow a verb_noun snake_case pattern (e.g., start_rail_run, get_run_status, verify_receipt). However, there are minor deviations like 'credential_aware_mcp_write' which is not verb-first, making it slightly inconsistent. Overall the naming is quite uniform.
89 tools is an extreme count, far beyond the typical 3-15 or even 25+. This suggests the server is trying to cover too many sub-domains, making the tool surface unwieldy and difficult to navigate.
The tool surface is extremely broad, covering discovery, quoting, payment, run lifecycle, receipts, credentials, directory submission, compliance, and verification. It lacks some expected operations like cancellation or refund, but these are niche and the core workflows are well-covered.