buy_trial_key$0.10 once. Use to try the paid tools: a prepaid key lt_... holding $0.10 of credit, sent as the X-API-Key header on POST /mcp or any paid HTTP route. A bearer secret. Larger credit: buy_api_key. No arguments.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| ok | No | ||
| data | No | ||
| meta | No | ||
| coverage | No |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "coverage": {
+ "type": "string"
+ },
+ "data": {
+ "type": [
+ "object",
+ "null"
+ ]
+ },
+ "meta": {
+ "type": "object"
+ },
+ "ok": {
+ "type": "boolean"
+ }
+ },
+ "type": "object"
+}Output schema / (root)Previous value: -{
- "anyOf": [
- {
- "properties": {
- "coverage": {
- "enum": [
- "full",
- "thin"
- ]
- },
- "data": {
- "properties": {
- "credit_usd": {
- "type": "number"
- },
- "key": {
- "type": "string"
- },
- "note": {
- "type": "string"
- },
- "status": {
- "type": "string"
- },
- "use": {
- "type": "object"
- }
- },
- "required": [
- "key",
- "credit_usd",
- "status",
- "use"
- ],
- "type": "object"
- },
- "meta": {
- "type": "object"
- },
- "ok": {
- "const": true
- }
- },
- "required": [
- "ok",
- "schema_version",
- "generated_at",
- "t",
- "coverage",
- "data",
- "meta"
- ],
- "type": "object"
- },
- {
- "properties": {
- "accepts": {
- "minItems": 1,
- "type": "array"
- },
- "x402Version": {
- "const": 2
- }
- },
- "required": [
- "x402Version",
- "accepts"
- ],
- "type": "object"
- },
- {
- "properties": {
- "error": {
- "type": "string"
- },
- "ok": {
- "const": false
- }
- },
- "required": [
- "ok",
- "error"
- ],
- "type": "object"
- }
- ],
- "type": "object"
-}New value: +nullInput schema / titleRemoved value: -"buy_trial_keyArguments"Output schema / anyOfPrevious value: -[
- {
- "properties": {
- "coverage": {
- "enum": [
- "full",
- "thin"
- ]
- },
- "data": {
- "properties": {
- "credit_usd": {
- "type": "number"
- },
- "key": {
- "type": "string"
- },
- "note": {
- "type": "string"
- },
- "status": {
- "type": "string"
- },
- "use": {
- "type": "object"
- }
- },
- "required": [
- "key",
- "credit_usd",
- "status",
- "use"
- ],
- "type": "object"
- },
- "generated_at": {
- "type": "string"
- },
- "meta": {
- "properties": {
- "feed_lag_s": {
- "type": [
- "number",
- "null"
- ]
- },
- "is_stale": {
- "type": "boolean"
- }
- },
- "type": "object"
- },
- "ok": {
- "const": true
- },
- "schema_version": {
- "type": "string"
- },
- "t": {
- "type": "number"
- }
- },
- "required": [
- "ok",
- "schema_version",
- "generated_at",
- "t",
- "coverage",
- "data",
- "meta"
- ],
- "title": "TrialKeyPurchase",
- "type": "object"
- },
- {
- "description": "isError: the x402 v2 payment requirements. Pay one accepts entry and call again with _meta['x402/payment']. error says why when a payment was sent and rejected; a failed settlement adds x402/payment-response. Nothing is charged.",
- "properties": {
- "accepts": {
- "items": {
- "properties": {
- "amount": {
- "type": "string"
- },
- "asset": {
- "type": "string"
- },
- "extra": {
- "type": "object"
- },
- "maxTimeoutSeconds": {
- "type": "integer"
- },
- "network": {
- "type": "string"
- },
- "payTo": {
- "type": "string"
- },
- "scheme": {
- "type": "string"
- }
- },
- "required": [
- "scheme",
- "network",
- "amount",
- "asset",
- "payTo"
- ],
- "type": "object"
- },
- "minItems": 1,
- "type": "array"
- },
- "error": {
- "type": "string"
- },
- "extensions": {
- "type": "object"
- },
- "resource": {
- "properties": {
- "description": {
- "type": "string"
- },
- "mimeType": {
- "type": "string"
- },
- "url": {
- "type": "string"
- }
- },
- "required": [
- "url"
- ],
- "type": "object"
- },
- "x402/payment-response": {
- "properties": {
- "errorReason": {
- "type": "string"
- },
- "network": {
- "type": "string"
- },
- "success": {
- "type": "boolean"
- },
- "transaction": {
- "type": "string"
- }
- },
- "required": [
- "success"
- ],
- "type": "object"
- },
- "x402Version": {
- "const": 2
- }
- },
- "required": [
- "x402Version",
- "resource",
- "accepts"
- ],
- "title": "PaymentRequired",
- "type": "object"
- },
- {
- "description": "isError: a refusal answered without charging (invalid or uncovered arguments, stale feed, nothing new since the cursor, a payment that cannot be matched to this request). error is a stable code; live_examples name mints covered now.",
- "properties": {
- "address": {
- "type": "string"
- },
- "avoid_skipped": {
- "type": "integer"
- },
- "case_mangled_mints": {
- "items": {
- "type": "string"
- },
- "type": "array"
- },
- "charged": {
- "type": [
- "boolean",
- "null"
- ]
- },
- "curve": {
- "type": "string"
- },
- "error": {
- "type": "string"
- },
- "feed_lag_s": {
- "type": [
- "number",
- "null"
- ]
- },
- "free_check": {
- "type": "string"
- },
- "got": {
- "type": [
- "string",
- "integer"
- ]
- },
- "hint": {
- "type": "string"
- },
- "invalid": {
- "type": "object"
- },
- "live_examples": {
- "items": {
- "type": "string"
- },
- "type": "array"
- },
- "max_feed_lag_s": {
- "type": "number"
- },
- "max_mints": {
- "type": "integer"
- },
- "max_table_lag_s": {
- "type": "number"
- },
- "message": {
- "type": "string"
- },
- "mint": {
- "type": "string"
- },
- "missing": {
- "items": {
- "type": "string"
- },
- "type": "array"
- },
- "newest_cursor": {
- "type": "string"
- },
- "ok": {
- "const": false
- },
- "payment_status": {
- "type": "string"
- },
- "scanned": {
- "type": "integer"
- },
- "schema": {
- "type": "object"
- },
- "since": {
- "type": [
- "string",
- "null"
- ]
- },
- "table_lag_s": {
- "type": [
- "number",
- "null"
- ]
- },
- "tool": {
- "type": "string"
- },
- "unavailable_mints": {
- "items": {
- "type": "string"
- },
- "type": "array"
- },
- "unverified_event": {
- "type": [
- "object",
- "null"
- ]
- },
- "window_s": {
- "type": "number"
- }
- },
- "required": [
- "ok",
- "error"
- ],
- "title": "Refusal",
- "type": "object"
- }
-]New value: +[
+ {
+ "properties": {
+ "coverage": {
+ "enum": [
+ "full",
+ "thin"
+ ]
+ },
+ "data": {
+ "properties": {
+ "credit_usd": {
+ "type": "number"
+ },
+ "key": {
+ "type": "string"
+ },
+ "note": {
+ "type": "string"
+ },
+ "status": {
+ "type": "string"
+ },
+ "use": {
+ "type": "object"
+ }
+ },
+ "required": [
+ "key",
+ "credit_usd",
+ "status",
+ "use"
+ ],
+ "type": "object"
+ },
+ "meta": {
+ "type": "object"
+ },
+ "ok": {
+ "const": true
+ }
+ },
+ "required": [
+ "ok",
+ "schema_version",
+ "generated_at",
+ "t",
+ "coverage",
+ "data",
+ "meta"
+ ],
+ "type": "object"
+ },
+ {
+ "properties": {
+ "accepts": {
+ "minItems": 1,
+ "type": "array"
+ },
+ "x402Version": {
+ "const": 2
+ }
+ },
+ "required": [
+ "x402Version",
+ "accepts"
+ ],
+ "type": "object"
+ },
+ {
+ "properties": {
+ "error": {
+ "type": "string"
+ },
+ "ok": {
+ "const": false
+ }
+ },
+ "required": [
+ "ok",
+ "error"
+ ],
+ "type": "object"
+ }
+]Output schema / descriptionRemoved value: -"One of three shapes. Success (isError false): the JSON envelope {ok, schema_version, generated_at, t, coverage, data, meta}. isError true: the x402 PaymentRequired {x402Version 2, resource, accepts[, error]} (pay and call again) or a refusal {ok: false, error, message, charged: false}; neither is charged."Output schema / (root)Previous value: -nullNew value: +{
+ "anyOf": [
+ {
+ "properties": {
+ "coverage": {
+ "enum": [
+ "full",
+ "thin"
+ ]
+ },
+ "data": {
+ "properties": {
+ "credit_usd": {
+ "type": "number"
+ },
+ "key": {
+ "type": "string"
+ },
+ "note": {
+ "type": "string"
+ },
+ "status": {
+ "type": "string"
+ },
+ "use": {
+ "type": "object"
+ }
+ },
+ "required": [
+ "key",
+ "credit_usd",
+ "status",
+ "use"
+ ],
+ "type": "object"
+ },
+ "generated_at": {
+ "type": "string"
+ },
+ "meta": {
+ "properties": {
+ "feed_lag_s": {
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "is_stale": {
+ "type": "boolean"
+ }
+ },
+ "type": "object"
+ },
+ "ok": {
+ "const": true
+ },
+ "schema_version": {
+ "type": "string"
+ },
+ "t": {
+ "type": "number"
+ }
+ },
+ "required": [
+ "ok",
+ "schema_version",
+ "generated_at",
+ "t",
+ "coverage",
+ "data",
+ "meta"
+ ],
+ "title": "TrialKeyPurchase",
+ "type": "object"
+ },
+ {
+ "description": "isError: the x402 v2 payment requirements. Pay one accepts entry and call again with _meta['x402/payment']. error says why when a payment was sent and rejected; a failed settlement adds x402/payment-response. Nothing is charged.",
+ "properties": {
+ "accepts": {
+ "items": {
+ "properties": {
+ "amount": {
+ "type": "string"
+ },
+ "asset": {
+ "type": "string"
+ },
+ "extra": {
+ "type": "object"
+ },
+ "maxTimeoutSeconds": {
+ "type": "integer"
+ },
+ "network": {
+ "type": "string"
+ },
+ "payTo": {
+ "type": "string"
+ },
+ "scheme": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "scheme",
+ "network",
+ "amount",
+ "asset",
+ "payTo"
+ ],
+ "type": "object"
+ },
+ "minItems": 1,
+ "type": "array"
+ },
+ "error": {
+ "type": "string"
+ },
+ "extensions": {
+ "type": "object"
+ },
+ "resource": {
+ "properties": {
+ "description": {
+ "type": "string"
+ },
+ "mimeType": {
+ "type": "string"
+ },
+ "url": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "url"
+ ],
+ "type": "object"
+ },
+ "x402/payment-response": {
+ "properties": {
+ "errorReason": {
+ "type": "string"
+ },
+ "network": {
+ "type": "string"
+ },
+ "success": {
+ "type": "boolean"
+ },
+ "transaction": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "success"
+ ],
+ "type": "object"
+ },
+ "x402Version": {
+ "const": 2
+ }
+ },
+ "required": [
+ "x402Version",
+ "resource",
+ "accepts"
+ ],
+ "title": "PaymentRequired",
+ "type": "object"
+ },
+ {
+ "description": "isError: a refusal answered without charging (invalid or uncovered arguments, stale feed, nothing new since the cursor, a payment that cannot be matched to this request). error is a stable code; live_examples name mints covered now.",
+ "properties": {
+ "address": {
+ "type": "string"
+ },
+ "avoid_skipped": {
+ "type": "integer"
+ },
+ "case_mangled_mints": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "charged": {
+ "type": [
+ "boolean",
+ "null"
+ ]
+ },
+ "curve": {
+ "type": "string"
+ },
+ "error": {
+ "type": "string"
+ },
+ "feed_lag_s": {
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "free_check": {
+ "type": "string"
+ },
+ "got": {
+ "type": [
+ "string",
+ "integer"
+ ]
+ },
+ "hint": {
+ "type": "string"
+ },
+ "invalid": {
+ "type": "object"
+ },
+ "live_examples": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "max_feed_lag_s": {
+ "type": "number"
+ },
+ "max_mints": {
+ "type": "integer"
+ },
+ "max_table_lag_s": {
+ "type": "number"
+ },
+ "message": {
+ "type": "string"
+ },
+ "mint": {
+ "type": "string"
+ },
+ "missing": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "newest_cursor": {
+ "type": "string"
+ },
+ "ok": {
+ "const": false
+ },
+ "payment_status": {
+ "type": "string"
+ },
+ "scanned": {
+ "type": "integer"
+ },
+ "schema": {
+ "type": "object"
+ },
+ "since": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "table_lag_s": {
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "tool": {
+ "type": "string"
+ },
+ "unavailable_mints": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "unverified_event": {
+ "type": [
+ "object",
+ "null"
+ ]
+ },
+ "window_s": {
+ "type": "number"
+ }
+ },
+ "required": [
+ "ok",
+ "error"
+ ],
+ "title": "Refusal",
+ "type": "object"
+ }
+ ],
+ "description": "One of three shapes. Success (isError false): the JSON envelope {ok, schema_version, generated_at, t, coverage, data, meta}. isError true: the x402 PaymentRequired {x402Version 2, resource, accepts[, error]} (pay and call again) or a refusal {ok: false, error, message, charged: false}; neither is charged.",
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare this is not read-only, is open-world, and not idempotent. The description adds crucial context: the key is prepaid with $0.10 of credit, is a bearer secret sent as X-API-Key, and is used on POST /mcp or any paid HTTP route. It also says 'no arguments,' which is helpful. However, it doesn't explain what happens after the trial credit is exhausted or whether the key can be reused.
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?
Extremely concise and front-loaded: price, purpose, key format, usage, alternative, and argument note, all in a few choppy but dense sentences. Every phrase 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?
Given the tool's simplicity (no parameters) and that an output schema exists, the description covers key aspects: cost, purpose, key format, and usage. It could mention what the return value contains (e.g., the key itself) but since an output schema exists, that is not strictly necessary.
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?
There are zero parameters, so the baseline is 4. The description's 'No arguments' is accurate and helps set expectations, though no additional parameter meaning is needed.
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?
States a specific action (buy a $0.10 trial key) and the resource (prepaid key with $0.10 credit). It also distinguishes from the sibling buy_api_key by specifying 'larger credit' for that alternative, so an agent can route correctly.
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?
Says 'Use to try the paid tools' and names the larger alternative buy_api_key, but doesn't explicitly state when not to use this or any eligibility constraints. Clear context for usage without full when-not guidance.
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.