Zinvyl Marketplace Agent Gateway

Preflight one agent purchase without creating an order

preflight_agent_purchase

Read-onlyIdempotent

Read-only transaction check. Verifies product match, credential, standing agent policy or narrower signed mandate, exact offer allowlist, price ceiling, current terms, sanitized scope, capacity, and payment-route readiness. It creates no intent, checkout, charge, order, or telemetry event.

Input Schema

Name	Required	Description
`buyer`	Yes
`task_summary`	Yes	One sanitized bounded outcome. Never include credentials, tokens, payment data, personal data, confidential files, or production secrets.
`purchase_authority`	Yes
`safe_scope_confirmed`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 28, 2026
- changedInput schema / properties / purchase_authority / properties / terms_version / const
```
Previous value: -"2026-10-23.6"New value: +"2026-10-27.1"
```

Changed2 schema fields changedOct 27, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1",
-  "zinvyl.data.csv-cleanup-starter.v1",
-  "zinvyl.data.csv-cleanup-complete.v1",
-  "zinvyl.analytics.operations-bi-dashboard.v1",
-  "zinvyl.quality.ai-workflow-failure-audit.v1",
-  "zinvyl.factory.workflow-single-automation-blueprint.v1",
-  "zinvyl.factory.development-mcp-server-starter.v1",
-  "zinvyl.factory.automation-compliant-market-monitor.v1",
-  "zinvyl.factory.content-instructional-video-pack.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1",
+  "zinvyl.analytics.operations-bi-dashboard.v1",
+  "zinvyl.quality.ai-workflow-failure-audit.v1",
+  "zinvyl.quality.trace-readiness-check.v1",
+  "zinvyl.factory.workflow-single-automation-blueprint.v1",
+  "zinvyl.factory.development-mcp-server-starter.v1",
+  "zinvyl.factory.automation-compliant-market-monitor.v1",
+  "zinvyl.factory.content-instructional-video-pack.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -16New value: +17
```

Changed2 schema fields changedOct 27, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1",
-  "zinvyl.data.csv-cleanup-starter.v1",
-  "zinvyl.data.csv-cleanup-complete.v1",
-  "zinvyl.analytics.operations-bi-dashboard.v1",
-  "zinvyl.quality.ai-workflow-failure-audit.v1",
-  "zinvyl.factory.workflow-single-automation-blueprint.v1",
-  "zinvyl.factory.development-mcp-server-starter.v1",
-  "zinvyl.factory.automation-compliant-market-monitor.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1",
+  "zinvyl.analytics.operations-bi-dashboard.v1",
+  "zinvyl.quality.ai-workflow-failure-audit.v1",
+  "zinvyl.factory.workflow-single-automation-blueprint.v1",
+  "zinvyl.factory.development-mcp-server-starter.v1",
+  "zinvyl.factory.automation-compliant-market-monitor.v1",
+  "zinvyl.factory.content-instructional-video-pack.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -15New value: +16
```

Changed2 schema fields changedOct 27, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1",
-  "zinvyl.data.csv-cleanup-starter.v1",
-  "zinvyl.data.csv-cleanup-complete.v1",
-  "zinvyl.analytics.operations-bi-dashboard.v1",
-  "zinvyl.quality.ai-workflow-failure-audit.v1",
-  "zinvyl.factory.workflow-single-automation-blueprint.v1",
-  "zinvyl.factory.development-mcp-server-starter.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1",
+  "zinvyl.analytics.operations-bi-dashboard.v1",
+  "zinvyl.quality.ai-workflow-failure-audit.v1",
+  "zinvyl.factory.workflow-single-automation-blueprint.v1",
+  "zinvyl.factory.development-mcp-server-starter.v1",
+  "zinvyl.factory.automation-compliant-market-monitor.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -14New value: +15
```

Changed1 schema field changedOct 27, 2026

changedInput schema / properties / buyer / properties / acquisition_channel / enum

Previous value: -[
-  "direct",
-  "direct_agent",
-  "mcp_registry",
-  "a2a_registry",
-  "ai_agents_directory",
-  "allagents",
-  "toku",
-  "gohirehumans",
-  "toll_bench",
-  "callboard",
-  "recruiting_bot",
-  "peerpush",
-  "speedbot",
-  "procurement_agent_operator",
-  "workflow_orchestrator",
-  "shopping_agent",
-  "partner_operator",
-  "other",
-  "zinvyl_offer_feed"
-]New value: +[
+  "direct",
+  "direct_agent",
+  "mcp_registry",
+  "a2a_registry",
+  "ai_agents_directory",
+  "allagents",
+  "toku",
+  "gohirehumans",
+  "toll_bench",
+  "callboard",
+  "recruiting_bot",
+  "peerpush",
+  "speedbot",
+  "lumen_b2b",
+  "procurement_agent_operator",
+  "workflow_orchestrator",
+  "shopping_agent",
+  "partner_operator",
+  "other",
+  "zinvyl_offer_feed"
+]

Changed1 schema field changedOct 27, 2026

changedInput schema / properties / buyer / properties / acquisition_channel / enum

Previous value: -[
-  "direct",
-  "direct_agent",
-  "mcp_registry",
-  "a2a_registry",
-  "ai_agents_directory",
-  "allagents",
-  "toku",
-  "gohirehumans",
-  "toll_bench",
-  "callboard",
-  "recruiting_bot",
-  "peerpush",
-  "procurement_agent_operator",
-  "workflow_orchestrator",
-  "shopping_agent",
-  "partner_operator",
-  "other",
-  "zinvyl_offer_feed"
-]New value: +[
+  "direct",
+  "direct_agent",
+  "mcp_registry",
+  "a2a_registry",
+  "ai_agents_directory",
+  "allagents",
+  "toku",
+  "gohirehumans",
+  "toll_bench",
+  "callboard",
+  "recruiting_bot",
+  "peerpush",
+  "speedbot",
+  "procurement_agent_operator",
+  "workflow_orchestrator",
+  "shopping_agent",
+  "partner_operator",
+  "other",
+  "zinvyl_offer_feed"
+]

Changed2 schema fields changedOct 26, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1",
-  "zinvyl.data.csv-cleanup-starter.v1",
-  "zinvyl.data.csv-cleanup-complete.v1",
-  "zinvyl.analytics.operations-bi-dashboard.v1",
-  "zinvyl.quality.ai-workflow-failure-audit.v1",
-  "zinvyl.factory.workflow-single-automation-blueprint.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1",
+  "zinvyl.analytics.operations-bi-dashboard.v1",
+  "zinvyl.quality.ai-workflow-failure-audit.v1",
+  "zinvyl.factory.workflow-single-automation-blueprint.v1",
+  "zinvyl.factory.development-mcp-server-starter.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -13New value: +14
```

Changed2 schema fields changedOct 26, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1",
-  "zinvyl.data.csv-cleanup-starter.v1",
-  "zinvyl.data.csv-cleanup-complete.v1",
-  "zinvyl.analytics.operations-bi-dashboard.v1",
-  "zinvyl.quality.ai-workflow-failure-audit.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1",
+  "zinvyl.analytics.operations-bi-dashboard.v1",
+  "zinvyl.quality.ai-workflow-failure-audit.v1",
+  "zinvyl.factory.workflow-single-automation-blueprint.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -12New value: +13
```

Changed2 schema fields changedOct 26, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1",
-  "zinvyl.data.csv-cleanup-starter.v1",
-  "zinvyl.data.csv-cleanup-complete.v1",
-  "zinvyl.analytics.operations-bi-dashboard.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1",
+  "zinvyl.analytics.operations-bi-dashboard.v1",
+  "zinvyl.quality.ai-workflow-failure-audit.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -11New value: +12
```

Changed1 schema field changedOct 25, 2026

changedInput schema / properties / buyer / properties / acquisition_channel / enum

Previous value: -[
-  "direct",
-  "direct_agent",
-  "mcp_registry",
-  "a2a_registry",
-  "ai_agents_directory",
-  "toku",
-  "gohirehumans",
-  "toll_bench",
-  "callboard",
-  "recruiting_bot",
-  "peerpush",
-  "procurement_agent_operator",
-  "workflow_orchestrator",
-  "shopping_agent",
-  "partner_operator",
-  "other",
-  "zinvyl_offer_feed"
-]New value: +[
+  "direct",
+  "direct_agent",
+  "mcp_registry",
+  "a2a_registry",
+  "ai_agents_directory",
+  "allagents",
+  "toku",
+  "gohirehumans",
+  "toll_bench",
+  "callboard",
+  "recruiting_bot",
+  "peerpush",
+  "procurement_agent_operator",
+  "workflow_orchestrator",
+  "shopping_agent",
+  "partner_operator",
+  "other",
+  "zinvyl_offer_feed"
+]

Changed1 schema field changedOct 25, 2026

changedInput schema / properties / buyer / properties / acquisition_channel / enum

Previous value: -[
-  "direct",
-  "direct_agent",
-  "mcp_registry",
-  "a2a_registry",
-  "ai_agents_directory",
-  "toku",
-  "gohirehumans",
-  "toll_bench",
-  "callboard",
-  "recruiting_bot",
-  "peerpush",
-  "procurement_agent_operator",
-  "workflow_orchestrator",
-  "shopping_agent",
-  "partner_operator",
-  "other"
-]New value: +[
+  "direct",
+  "direct_agent",
+  "mcp_registry",
+  "a2a_registry",
+  "ai_agents_directory",
+  "toku",
+  "gohirehumans",
+  "toll_bench",
+  "callboard",
+  "recruiting_bot",
+  "peerpush",
+  "procurement_agent_operator",
+  "workflow_orchestrator",
+  "shopping_agent",
+  "partner_operator",
+  "other",
+  "zinvyl_offer_feed"
+]

Changed1 schema field changedOct 24, 2026
- changedInput schema / properties / purchase_authority / properties / terms_version / const
```
Previous value: -"2026-10-23.4"New value: +"2026-10-23.6"
```
Changed1 schema field changedOct 24, 2026
- changedInput schema / properties / purchase_authority / properties / terms_version / const
```
Previous value: -"2026-10-23.3"New value: +"2026-10-23.4"
```
Changed1 schema field changedOct 24, 2026
- changedInput schema / properties / purchase_authority / properties / terms_version / const
```
Previous value: -"2026-10-23.2"New value: +"2026-10-23.3"
```
Changed1 schema field changedOct 24, 2026
- changedInput schema / properties / purchase_authority / properties / terms_version / const
```
Previous value: -"2026-10-13.1"New value: +"2026-10-23.2"
```

Changed2 schema fields changedOct 23, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1",
-  "zinvyl.data.csv-cleanup-starter.v1",
-  "zinvyl.data.csv-cleanup-complete.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1",
+  "zinvyl.analytics.operations-bi-dashboard.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -10New value: +11
```

Changed2 schema fields changedOct 23, 2026

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / items / enum

Previous value: -[
-  "zinvyl.venture.evidence-brief.v1",
-  "zinvyl.venture.prototype-scope.v1",
-  "zinvyl.freight.workflow-audit.v1",
-  "zinvyl.api.workflow-failure-rescue.v1",
-  "zinvyl.api.failure-triage.v1",
-  "zinvyl.api.workflow-reliability-care.v1",
-  "zinvyl.freight.full-workflow-audit.v1",
-  "zinvyl.content.ai-marketing-pilot.v1"
-]New value: +[
+  "zinvyl.venture.evidence-brief.v1",
+  "zinvyl.venture.prototype-scope.v1",
+  "zinvyl.freight.workflow-audit.v1",
+  "zinvyl.api.workflow-failure-rescue.v1",
+  "zinvyl.api.failure-triage.v1",
+  "zinvyl.api.workflow-reliability-care.v1",
+  "zinvyl.freight.full-workflow-audit.v1",
+  "zinvyl.content.ai-marketing-pilot.v1",
+  "zinvyl.data.csv-cleanup-starter.v1",
+  "zinvyl.data.csv-cleanup-complete.v1"
+]

changedInput schema / properties / purchase_authority / properties / allowed_offer_ids / maxItems
```
Previous value: -8New value: +10
```

Changed3 schema fields changedOct 21, 2026

changedInput schema / properties / purchase_authority / properties / funding_method / description

Previous value: -"Use auto unless the buyer client requires a specific rail. Auto defaults to Stripe-hosted checkout, which does not require prior Zinvyl customer payment-method enrollment. Legacy hosted card and ACH values remain accepted as aliases."New value: +"Use auto unless the buyer client requires a specific rail. Auto selects the owner-enrolled delegated card when the authenticated agent's organization has one; otherwise it returns hosted checkout. Legacy hosted card and ACH values remain accepted as aliases."

changedInput schema / properties / purchase_authority / properties / mandate_token / description

Previous value: -"Optional principal-issued signed single-transaction mandate. Required when Zinvyl's signed-mandate enforcement is enabled."New value: +"Optional principal-issued signed single-transaction restriction. Non-delegated-card autonomous routes require it; delegated card may instead use the active agent's owner-issued standing allowlist and ceiling."

changedInput schema / properties / purchase_authority / properties / payment_capabilities / description

Previous value: -"Optional client capabilities used for adaptive routing. Omit to receive the broadly compatible Stripe-hosted checkout route."New value: +"Optional client capabilities used for adaptive routing. An active organization delegated-card enrollment takes precedence for auto."

Changed4 schema fields changedOct 21, 2026

addedInput schema / properties / purchase_authority / properties / funding_method / default
```
Added value: +"auto"
```

changedInput schema / properties / purchase_authority / properties / funding_method / description

Previous value: -"Choose stripe_delegated_card only when an organization owner or administrator has completed the Stripe-hosted saved-card setup; otherwise use stripe_mpp_card."New value: +"Use auto unless the buyer client requires a specific rail. Auto defaults to Stripe-hosted checkout, which does not require prior Zinvyl customer payment-method enrollment. Legacy hosted card and ACH values remain accepted as aliases."

changedInput schema / properties / purchase_authority / properties / funding_method / enum

Previous value: -[
-  "stripe_mpp_card",
-  "stripe_delegated_card"
-]New value: +[
+  "auto",
+  "stripe_hosted_checkout",
+  "stripe_delegated_card",
+  "stripe_mpp_card",
+  "stripe_hosted_card",
+  "stripe_hosted_ach"
+]

addedInput schema / properties / purchase_authority / properties / payment_capabilities

Added value: +{
+  "description": "Optional client capabilities used for adaptive routing. Omit to receive the broadly compatible Stripe-hosted checkout route.",
+  "items": {
+    "enum": [
+      "checkout:stripe",
+      "delegated:stripe",
+      "mpp:stripe",
+      "card",
+      "bank:ach",
+      "wallet:apple_pay",
+      "wallet:google_pay",
+      "wallet:link"
+    ],
+    "type": "string"
+  },
+  "maxItems": 8,
+  "type": "array"
+}

Changed1 schema field changedOct 20, 2026

addedInput schema / properties / purchase_authority / properties / funding_method

Added value: +{
+  "description": "Choose stripe_delegated_card only when an organization owner or administrator has completed the Stripe-hosted saved-card setup; otherwise use stripe_mpp_card.",
+  "enum": [
+    "stripe_mpp_card",
+    "stripe_delegated_card"
+  ],
+  "type": "string"
+}

AddedOct 18, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the bar is lower, but the description still adds real value by enumerating exactly what is NOT produced (no intent, checkout, charge, order, telemetry) — a precise side-effect disclosure an agent needs before chaining. It stops short of stating auth prerequisites or failure modes, which the mandate/credential requirements would warrant.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the read-only framing and closing with the strongest disambiguator. The verification list is dense but each clause carries distinct information; it could be tightened by grouping the checks rather than running nine items together.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a four-parameter nested verification tool with no output schema, the description should hint at what a successful check returns (matched offer, continuation token, blocking reasons). It covers inputs and side effects but says nothing about the response, leaving an agent unsure how to interpret the result or when to proceed to create_purchase_intent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 25% and the object is deeply nested, so the description partly compensates by naming the concepts checked — offer allowlist, price ceiling, current terms, sanitized scope, standing policy or narrower signed mandate — which map onto allowed_offer_ids, maximum_amount, terms_version, task_summary and mandate_token. However it never ties these to parameter names and leaves continuation_token, acquisition_channel, funding_method and payment_capabilities unaddressed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('read-only transaction check' that 'verifies product match, credential, ... payment-route readiness') and explicitly separates itself from order-creating siblings by denying it 'creates no intent, checkout, charge, order, or telemetry event.' An agent can distinguish it from create_purchase_intent or buy_service without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The 'read-only' framing and the negative-effects sentence imply this is the validate-first step before a real purchase, but the description never names an alternative (prepare_purchase_route, get_purchase_requirements, create_purchase_intent) or states the condition that selects this tool over them. Usage is inferable rather than stated.

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

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