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[Feature Request] Add spending limits and policy controls for agent payments #31

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[Feature Request] Add spending limits and policy controls for agent payments#31

Description

@mkmkkkkk
mkmkkkkk
opened on Feb 7, 2026

Problem

MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."

Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:

  • Cumulative budgets — hourly/daily/monthly spend limits
  • Rate limiting — max N transactions per time window
  • Recipient allowlists/blocklists — restrict which addresses an agent can pay
  • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
  • Human-in-the-loop approval — flag transactions above a threshold for manual review

As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.

Proposal

Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.

Possible interface

constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})

Where it fits in the flow

In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:

402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.

Existing work

PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.

Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.

Why this matters for MCPay

MCPay is positioned as the payment infra for MCP. Adding governance/controls would:

  1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
  2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
  3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker

Happy to discuss implementation approaches or contribute if there's interest.

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[Feature Request] Add spending limits and policy controls for agent payments · Issue #31 · microchipgnu/MCPay · GitHub
      Skip to content
      [Feature Request] Add spending limits and policy controls for agent payments #31
      Open
      Open
      [Feature Request] Add spending limits and policy controls for agent payments#31
      Description
      @mkmkkkkk
      mkmkkkkk
      opened on Feb 7, 2026
      Problem
      MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."
      Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:
      • Cumulative budgets — hourly/daily/monthly spend limits
      • Rate limiting — max N transactions per time window
      • Recipient allowlists/blocklists — restrict which addresses an agent can pay
      • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
      • Human-in-the-loop approval — flag transactions above a threshold for manual review
      As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.
      Proposal
      Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.
      Possible interface
      constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})
      Where it fits in the flow
      In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:
      402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

      This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.
      Existing work
      PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.
      Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.
      Why this matters for MCPay
      MCPay is positioned as the payment infra for MCP. Adding governance/controls would:
      1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
      2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
      3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker
      Happy to discuss implementation approaches or contribute if there's interest.
      Metadata
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[Feature Request] Add spending limits and policy controls for agent payments · Issue #31 · microchipgnu/MCPay · GitHub
          Skip to content
          [Feature Request] Add spending limits and policy controls for agent payments #31
          Open
          Open
          [Feature Request] Add spending limits and policy controls for agent payments#31
          Description
          @mkmkkkkk
          mkmkkkkk
          opened on Feb 7, 2026
          Problem
          MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."
          Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:
          • Cumulative budgets — hourly/daily/monthly spend limits
          • Rate limiting — max N transactions per time window
          • Recipient allowlists/blocklists — restrict which addresses an agent can pay
          • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
          • Human-in-the-loop approval — flag transactions above a threshold for manual review
          As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.
          Proposal
          Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.
          Possible interface
          constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})
          Where it fits in the flow
          In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:
          402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

          This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.
          Existing work
          PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.
          Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.
          Why this matters for MCPay
          MCPay is positioned as the payment infra for MCP. Adding governance/controls would:
          1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
          2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
          3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker
          Happy to discuss implementation approaches or contribute if there's interest.
          Metadata
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[Feature Request] Add spending limits and policy controls for agent payments · Issue #31 · microchipgnu/MCPay · GitHub
              Skip to content
              [Feature Request] Add spending limits and policy controls for agent payments #31
              Open
              Open
              [Feature Request] Add spending limits and policy controls for agent payments#31
              Description
              @mkmkkkkk
              mkmkkkkk
              opened on Feb 7, 2026
              Problem
              MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."
              Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:
              • Cumulative budgets — hourly/daily/monthly spend limits
              • Rate limiting — max N transactions per time window
              • Recipient allowlists/blocklists — restrict which addresses an agent can pay
              • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
              • Human-in-the-loop approval — flag transactions above a threshold for manual review
              As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.
              Proposal
              Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.
              Possible interface
              constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})
              Where it fits in the flow
              In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:
              402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

              This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.
              Existing work
              PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.
              Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.
              Why this matters for MCPay
              MCPay is positioned as the payment infra for MCP. Adding governance/controls would:
              1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
              2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
              3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker
              Happy to discuss implementation approaches or contribute if there's interest.
              Metadata
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var __re = new RegExp('^' + "youtube\\.com" + '
[Feature Request] Add spending limits and policy controls for agent payments · Issue #31 · microchipgnu/MCPay · GitHub
                  Skip to content
                  [Feature Request] Add spending limits and policy controls for agent payments #31
                  Open
                  Open
                  [Feature Request] Add spending limits and policy controls for agent payments#31
                  Description
                  @mkmkkkkk
                  mkmkkkkk
                  opened on Feb 7, 2026
                  Problem
                  MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."
                  Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:
                  • Cumulative budgets — hourly/daily/monthly spend limits
                  • Rate limiting — max N transactions per time window
                  • Recipient allowlists/blocklists — restrict which addresses an agent can pay
                  • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
                  • Human-in-the-loop approval — flag transactions above a threshold for manual review
                  As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.
                  Proposal
                  Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.
                  Possible interface
                  constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})
                  Where it fits in the flow
                  In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:
                  402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

                  This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.
                  Existing work
                  PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.
                  Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.
                  Why this matters for MCPay
                  MCPay is positioned as the payment infra for MCP. Adding governance/controls would:
                  1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
                  2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
                  3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker
                  Happy to discuss implementation approaches or contribute if there's interest.
                  Metadata
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var __m = "*";
var __re = new RegExp('^' + ".*" + '
[Feature Request] Add spending limits and policy controls for agent payments · Issue #31 · microchipgnu/MCPay · GitHub
                      Skip to content
                      [Feature Request] Add spending limits and policy controls for agent payments #31
                      Open
                      Open
                      [Feature Request] Add spending limits and policy controls for agent payments#31
                      Description
                      @mkmkkkkk
                      mkmkkkkk
                      opened on Feb 7, 2026
                      Problem
                      MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."
                      Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:
                      • Cumulative budgets — hourly/daily/monthly spend limits
                      • Rate limiting — max N transactions per time window
                      • Recipient allowlists/blocklists — restrict which addresses an agent can pay
                      • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
                      • Human-in-the-loop approval — flag transactions above a threshold for manual review
                      As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.
                      Proposal
                      Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.
                      Possible interface
                      constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})
                      Where it fits in the flow
                      In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:
                      402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

                      This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.
                      Existing work
                      PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.
                      Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.
                      Why this matters for MCPay
                      MCPay is positioned as the payment infra for MCP. Adding governance/controls would:
                      1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
                      2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
                      3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker
                      Happy to discuss implementation approaches or contribute if there's interest.
                      Metadata
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                      No one assigned
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                        No labels
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[Feature Request] Add spending limits and policy controls for agent payments · Issue #31 · microchipgnu/MCPay · GitHub
                          Skip to content
                          [Feature Request] Add spending limits and policy controls for agent payments #31
                          Open
                          Open
                          [Feature Request] Add spending limits and policy controls for agent payments#31
                          Description
                          @mkmkkkkk
                          mkmkkkkk
                          opened on Feb 7, 2026
                          Problem
                          MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."
                          Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:
                          • Cumulative budgets — hourly/daily/monthly spend limits
                          • Rate limiting — max N transactions per time window
                          • Recipient allowlists/blocklists — restrict which addresses an agent can pay
                          • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
                          • Human-in-the-loop approval — flag transactions above a threshold for manual review
                          As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.
                          Proposal
                          Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.
                          Possible interface
                          constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})
                          Where it fits in the flow
                          In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:
                          402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

                          This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.
                          Existing work
                          PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.
                          Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.
                          Why this matters for MCPay
                          MCPay is positioned as the payment infra for MCP. Adding governance/controls would:
                          1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
                          2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
                          3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker
                          Happy to discuss implementation approaches or contribute if there's interest.
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[Feature Request] Add spending limits and policy controls for agent payments · Issue #31 · microchipgnu/MCPay · GitHub
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                              [Feature Request] Add spending limits and policy controls for agent payments #31
                              Open
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                              [Feature Request] Add spending limits and policy controls for agent payments#31
                              Description
                              @mkmkkkkk
                              mkmkkkkk
                              opened on Feb 7, 2026
                              Problem
                              MCPay handles the payment lifecycle elegantly — 402 negotiation, on-chain settlement, transparent retries. But once an agent has wallet access, there's no enforcement layer between "agent wants to pay" and "payment goes on-chain."
                              Today, maxPaymentValue in withX402Client is the only guardrail, and it's a static per-transaction cap set at init time. There's no way to enforce:
                              • Cumulative budgets — hourly/daily/monthly spend limits
                              • Rate limiting — max N transactions per time window
                              • Recipient allowlists/blocklists — restrict which addresses an agent can pay
                              • Per-tool policies — different limits for different tool calls (e.g. a $0.001 weather lookup vs. a $5 data export)
                              • Human-in-the-loop approval — flag transactions above a threshold for manual review
                              As agents gain more financial autonomy, the gap between "can pay" and "should pay" becomes a real risk surface.
                              Proposal
                              Add a policy engine that evaluates every payment against configurable rules before it hits the chain. Conceptually, this sits between the x402 negotiation and the actual signing step.
                              Possible interface
                              constpaymentClient=withX402Client(client,{wallet: {evm: evmSigner},policy: {maxPerTransaction: 0.10,// USDCmaxPerHour: 1.00,maxPerDay: 10.00,allowedRecipients: ["0x..."],// optional allowlistrequireApproval: {above: 5.00,// flag for human reviewcallback: async(tx)=>{/* webhook / UI prompt */}}}})
                              Where it fits in the flow
                              In the existing sequence diagram, the policy check would happen at steps (5a)/(6b) — after the 402 metadata is received but before signing/broadcasting the transaction:
                              402 received → policy.evaluate(amount, recipient, tool, context) → allow/deny/escalate → sign → broadcast

                              This keeps it non-breaking — the policy engine is opt-in and the default behavior (no policy = allow all) stays the same.
                              Existing work
                              PaySentry is an open-source SDK that implements this pattern for x402 payments — per-transaction limits, rolling budgets, recipient controls, and observability hooks. Its @paysentry/control package specifically handles the policy evaluation step.
                              Could be worth looking at as a reference implementation or potential integration path. The core idea (evaluate-before-sign) is what matters, regardless of which library implements it.
                              Why this matters for MCPay
                              MCPay is positioned as the payment infra for MCP. Adding governance/controls would:
                              1. Unlock enterprise adoption — no finance team will approve agent wallets without spending controls
                              2. Differentiate from raw x402 — x402 handles the protocol, MCPay + policy handles the trust layer
                              3. Reduce liability — if an agent misbehaves, the policy engine is the circuit breaker
                              Happy to discuss implementation approaches or contribute if there's interest.
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                No labels
                                No labels
                                Projects
                                No projects
                                  Milestone
                                  No milestone
                                  Relationships
                                  None yet
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                                  Issue actions