Discover and call pay-per-request (x402) APIs, ranked by reliability, latency and price.
Scored across 3 tools
Each tool targets a distinct action: listing capabilities, discovering endpoints for a capability, and calling a discovered endpoint. No overlap in purpose.
All tool names follow a consistent verb_noun pattern (list_capabilities, discover_paid_api, call_paid_api), making the set easy to navigate.
Three tools is well-scoped for the server's purpose of discovering and calling paid APIs. Each tool serves a necessary step in the workflow.
The core workflow (list capabilities, discover endpoints, call endpoints) is covered. Minor missing features like checking payment status or endpoint details without discovery are not critical given the design.
Call a previously discovered API endpoint.
Use this after discover_paid_api to execute the request.
IMPORTANT: You must first use discover_paid_api to find an endpoint. Then use the endpoint_id from the discovery result. Use the sample_request from the discovery result as your body template — it shows the exact parameter names the endpoint expects. Replace the example values with the actual values you need.
Payment: this hosted server holds no wallet, so it cannot settle x402 payments. Free endpoints return their data directly. Paid endpoints return the payment challenge (amount, recipient, network) without charging anything. To pay automatically, run the local server instead: npx @entroute/mcp-server with EVM_PRIVATE_KEY set.
Trust & safety:
EntRoute verifies that endpoints return valid 402 responses every 10 minutes, but does not guarantee response quality or accuracy. Treat results like any third-party API.
Prefer endpoints with high success rates (>95%) and recent verification timestamps.
| Name | Required | Description | Default |
|---|---|---|---|
| body | No | Request body (for POST/PUT/PATCH) | |
| method | No | HTTP method (defaults to endpoint method) | |
| headers | No | Additional headers to include in the request | |
| endpoint_id | Yes | The endpoint_id from a previous discover_paid_api result | |
| query_params | No | Query parameters to append to URL |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so the description bears full responsibility. It discloses that the hosted server cannot settle payments, describes the behavior for free vs paid endpoints, and details the trust & safety aspects (verification intervals, success rate recommendations). This goes well beyond the schema and provides essential behavioral context.
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 thorough but well-structured with clear sections (IMPORTANT, Payment, Trust & safety). It front-loads the core purpose and prerequisite. Some redundancy exists (e.g., repeated mention of discover_paid_api), but overall it is concise for the amount of context needed.
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's complexity (5 parameters, workflow dependency, payment handling), the description covers all necessary aspects: prerequisite tool, how to construct the request, payment behavior, and safety guidelines. No output schema exists, but the description appropriately focuses on input and behavior.
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% with basic descriptions for each parameter. The description adds significant workflow context: explains how endpoint_id relates to discover_paid_api, and mentions using sample_request as a body template. This enhances understanding beyond the schema, though it does not add per-parameter details.
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 clearly states the tool's action: 'Call a previously discovered API endpoint.' It specifies the prerequisite (use after discover_paid_api) and distinguishes from the sibling discover_paid_api, which handles discovery. The verb 'call' and resource 'API endpoint' are specific and 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?
Explicitly states when to use: after discover_paid_api. Provides step-by-step guidance: use endpoint_id and sample_request from discovery. Explains payment scenarios (free vs paid) and recommends the local server for automatic payment. No explicit 'when not to use', but the context is sufficiently clear to avoid misuse.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Discover pay-per-request API endpoints for a given capability.
Returns ranked, verified endpoints with pricing and reliability metrics. Use this to find APIs before calling them. The results include:
Endpoint URL and method
Price per call and payment network
Success rate and latency metrics
Provider information
sample_request / sample_response: Example request body and response showing the exact parameter names and format the endpoint expects. ALWAYS use sample_request as your template when calling the endpoint — do not guess parameter names.
After discovering, you can use call_paid_api to execute the endpoint.
Trust & safety:
"Verified" means the endpoint returns a valid x402 402 response -- it does not guarantee the quality or accuracy of the data returned after payment.
Endpoints are probed every 10 minutes. Check last_verified and success_rate to gauge reliability.
Fallback endpoints (unverified) have failed recent verification checks -- use with caution.
Prefer endpoints with success_rate >95% and verification within the last 24 hours.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Maximum number of endpoints to return (default: 5) | |
| intent | Yes | Natural language description of what you want to do (e.g., "get current weather for London", "translate text to Spanish"). Provide this or capability_id. | |
| network | No | Required blockchain network for payment | |
| max_price | No | Maximum price per request in USD (e.g., 0.01 for 1 cent) | |
| capability_id | No | Explicit capability ID if known (e.g., "weather.current", "translate.text"). Alternative to intent for precise matching. | |
| ranking_preset | No | Ranking preference preset |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so the description carries full burden. It discloses that 'Verified' means a valid 402 response, not data quality. Mentions probing every 10 minutes, last_verified, success_rate, fallback endpoints, and the importance of using sample_request as a template.
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?
Well-structured with bullet points and clear sections. Front-loaded with purpose. Slightly lengthy but each sentence adds value. Could be slightly more concise, but overall effective.
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 6 parameters, no output schema, and no annotations, the description is highly complete. It covers tool purpose, return structure, parameter guidance, trust/safety info, and usage flow. No significant 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?
Schema description coverage is 100%, baseline is 3. The description adds extra context: explains sample_request/response usage, describes 'intent' as natural language description, and provides guidance on parameter usage. Adds meaningful value beyond schema.
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 clearly states 'Discover pay-per-request API endpoints for a given capability' and lists what it returns (URL, method, pricing, reliability, provider, sample_request/response). It distinguishes itself from sibling tools 'call_paid_api' (execution) and 'list_capabilities' (listing capabilities).
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?
Explicitly says 'Use this to find APIs before calling them' and mentions using 'call_paid_api' after discovery. Provides guidance on preferring endpoints with high success rates and recent verification. No explicit exclusion of alternatives, but the context is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
List available API capability types.
Use this to explore what kinds of APIs are available in the registry. You can filter by tag (e.g., "weather", "translation") or search by keyword.
Note: A capability existing does not mean verified endpoints are available for it. Use discover_paid_api to check for live endpoints.
| Name | Required | Description | Default |
|---|---|---|---|
| tag | No | Filter by tag (e.g., "weather", "translation", "finance") | |
| search | No | Search capabilities by keyword |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so description carries full burden. It discloses that capabilities listed may not have verified endpoints, indicating non-destructive, read-like behavior. Does not explicitly state 'read-only' but is sufficiently transparent about limitations.
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?
Relatively concise (3 sentences + note). Front-loaded with main purpose. Could potentially merge the note into the second sentence, but overall efficient and clear.
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?
No output schema and no description of return format, fields, or pagination. Given that this is a list operation, agents would benefit from knowing the structure of returned capability types. Lacks this detail despite low complexity.
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% with descriptions for both parameters. Description adds filter/search examples ('weather', 'translation') and ties to tool purpose, but does not provide significant new meaning beyond schema.
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 clearly states 'List available API capability types' with a specific verb and resource. It distinguishes from siblings (call_paid_api, discover_paid_api) by focusing on exploration rather than execution or endpoint validation.
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?
Explicitly tells when to use the tool (explore capabilities, filter by tag/search) and when not to (capability existence does not guarantee live endpoints, directing to discover_paid_api for that). Provides clear usage context and alternative.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
call_paid_apidiscover_paid_apilist_capabilitiesDiscover and call 2,000+ x402 machine-payable services through one graded API key + gateway.
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Pay-per-call AI gateway: models, speech, web search, on-chain reads and NLP tools, via x402.
180+ pay-per-call data APIs via x402, no API key: research, law, medical, security, markets, crypto.
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