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MCP connects an agent to tools, APIs, and data; A2A connects one agent to another for discovery, delegation, and task exchange. In banking, financial services, and insurance (BFSI), they solve different interoperability problems and can work together—but neither protocol supplies the identity, authorization, oversight, or regulatory controls a financial institution needs.
MCP vs. A2A: what each protocol does
The simplest distinction is the connection being standardized. A2A’s official overview describes MCP as agent-to-tool communication and A2A as agent-to-agent communication. They are complementary layers, not alternatives.
| Question | MCP | A2A |
|---|---|---|
| Connects | An AI application or agent to a server exposing tools, APIs, or data resources. | Distinct agent systems to one another. |
| Typical purpose | Read information or invoke a specific capability, such as retrieving a record or submitting a request. | Discover a peer’s declared capabilities and delegate a defined task. |
| What it does not establish by itself | That a caller is authorized for a business action, that a result is reliable, or that access complies with policy. | That a discovered agent is trusted, authorized for a task, or safe to rely on. |
For example, a servicing agent might use A2A to delegate a document-review task to a specialist agent. That specialist could use MCP to retrieve approved records or call a narrowly scoped internal tool. A2A carries the agent-to-agent interaction; MCP connects an agent to capabilities exposed by servers.
How the protocols fit into a BFSI architecture
A useful design separates the interaction layers from the controls that govern them. The following is an implementation model, not an official reference architecture or a requirement imposed by either protocol.
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| Layer | Role | Key design question |
|---|---|---|
| User or channel and policy | Authenticates the human or calling system and establishes the request’s purpose and applicable policy context. | Who initiated the request, and what are they permitted to ask? |
| Orchestrating agent | Interprets the request, determines whether delegation is needed, and acts only within its authorization boundary. | Which steps are allowed, and which require review? |
| A2A peer agents | Advertise capabilities and accept authorized task requests from other agents. | Is this peer’s declared capability suitable for this task, and is the task authorized? |
| MCP servers | Expose scoped tools and resources to agents. | Which data or actions can this agent access in this environment? |
| Control plane | Spans the interactions with identity, authorization, secrets, policy checks, audit, monitoring, incident response, evaluation, and provider governance. | Can the institution demonstrate who or what acted, under what authority, and with what outcome? |
A protocol defines an interoperability contract; it does not, by itself, provide identity assurance, business authorization, data residency, reliable model behavior, or regulatory compliance. Treat each connected server and peer agent as a distinct trust boundary, even when the systems can communicate successfully.
What to verify in the protocols and their versions
MCP request state and transport
The MCP basic specification dated 28 July 2026 identifies MCP as stateless: each request must carry the information needed to process it. An implementation should not infer conversation state, identity, or protocol metadata from an earlier request merely because it arrived over the same connection. If work depends on prior state, reference that state explicitly and protect it with the application’s own access controls. See the dated MCP specification.
Authentication also depends on transport. The inspected MCP specification’s HTTP authorization framework applies to HTTP transports; it says STDIO implementations should not use that HTTP framework and should obtain credentials from the environment. Choose and document authentication for the transport actually deployed rather than treating one setup as universal.
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A2A discovery and task boundaries
A2A Agent Cards describe an agent’s identity, capabilities, skills, endpoint, and authentication requirements. A card helps a caller discover what a peer says it can do; it is not permission to invoke those capabilities. The caller and receiving service still need their own identity checks and authorization decisions. A2A’s security and data-protection expectations include enforcing authorization boundaries, validating content, sanitizing user-provided material, and protecting sensitive task history and artifacts. Confirm the exact implementation details against the release you pin.
Pin releases and check interoperability
The A2A documentation identifies 1.0.0 as its latest released version, while the MCP source cited here is dated 28 July 2026. Pin the protocol and SDK versions used in each deployment, test interoperability across the actual implementations, and verify compatibility before upgrading; a moving development specification is not a substitute for a pinned release.
A secure implementation path for a BFSI pilot
The sequence below is practical implementation advice synthesized from the protocol and supervisory material; it is not an official regulator checklist. Adapt it to the institution, jurisdiction, function, and use case.
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- Choose a bounded workflow. Select a use case with defined data boundaries and observable outcomes. Decide whether the agent only retrieves and summarizes information or can initiate transactions, change records, communicate externally, or affect a customer decision.
- Classify data and consequences. Map customer information, payment data, credentials, internal records, and third-party data. For each tool action, identify its impact and reversibility. Make read access and write access separate risk decisions.
- Define trust zones and identities. Assign each agent and MCP server an explicit workload identity. Scope credentials to the specific tools, resources, and environments required. Do not use a transport connection as a substitute for identity or session context.
- Set action controls. Require human review for material, irreversible, customer-impacting, or money-moving actions unless a documented control case supports automation. Where appropriate, use transaction limits, allowlists, idempotency, and independent authorization checks. Human approval reduces some risks but is not a guarantee that a request is correct.
- Protect instruction boundaries and tools. Treat retrieved documents, customer input, and database values as untrusted data, not instructions. Vet servers before installation, inspect their permissions and outputs, and test prompt injection and unexpected tool chaining. Deny read-write access to production resources when the workflow does not need it.
- Constrain delegation. Delegate a defined task only to a peer whose declared capability is needed. Validate its Agent Card and endpoint, authenticate requests, authorize each operation, limit task scope, and inspect returned artifacts before downstream use. Preserve task provenance rather than inferring trust from protocol compatibility.
- Instrument and test. Log actor or agent identity, tool or peer, authorized scope, request or task identifiers, policy decisions, approvals, outcomes, and errors, while minimizing sensitive data in logs. Test malformed inputs, prompt injection, authorization bypass, duplicate requests, timeouts, partial results, retries, and service outages.
- Review providers and resilience. Inventory direct and subcontracted providers, critical dependencies, data access, incident communications, audit rights, service continuity, and exit or portability options. Assess concentration and recovery risks as well as the individual provider’s controls.
- Roll out in stages. Start in a sandbox with synthetic or approved data, compare outputs with a controlled baseline, and run security and resilience tests. Move to read-only production where suitable; enable bounded writes only after control evidence, owners, rollback, and incident processes are approved.
Security risks that matter in financial workflows
Connecting tools creates the possibility that an agent will read sensitive data or take consequential action. Google Cloud’s MCP security guidance notes that MCP servers can expose actions that make non-reversible resource changes. It distinguishes human-in-the-middle use from agent-only operation and warns that agent-only use depends on programming and can be vulnerable to prompt injection, insecure tool chaining, and naive error handling.
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- Untrusted content: Retrieved files, messages, and database fields can contain instructions designed to redirect an agent. Treat them as data and test how tools behave when that content conflicts with system policy.
- Excessive permissions: A broad credential can turn a small task into an unauthorized read or write. Restrict available capabilities and production access to what the workflow needs.
- Delegated work: A peer agent may return incomplete, malformed, or unsafe artifacts. Check provenance and validate outputs before using them in a decision or passing them to another tool.
- Operational failure: Retries, duplicated requests, timeouts, and partial responses can produce incorrect or repeated actions. Define recovery behavior and test it before granting write authority.
Governance and regulatory context
European Union
A joint EBA, EIOPA, and ESMA statement published on 31 July 2026 calls for robust governance and risk management to mitigate cyber risks associated with frontier AI models. The EBA Risk Assessment Report for June 2026 says banks should integrate AI use into their DORA compliance framework and consider potential AI Act implications. The report also states that 56% of banks had not been victims of a cyberattack resulting, or potentially resulting, in a “major ICT-related incident” in the first half of 2026. That figure concerns the report’s specified period and incident definition; it is not a measure of all cyberattacks or all financial institutions.
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On 18 September 2026, the EBA announced final third-party risk guidelines focused on arrangements supporting critical or important functions. The announcement covers risk assessment and due diligence, contracting, subcontracting, monitoring, documentation, and exit strategies, and states a two-year transitional period. Check the ESAs statement and the EBA announcement for the source material, and verify final text, applicability, and dates with the institution’s compliance function before treating a provision as binding for a particular entity.
United States
The OCC’s 2026 revised model risk guidance says generative and agentic AI are outside that guidance’s scope and that the guidance is not prescriptive or enforceable. This is not a statement that agentic AI is unregulated: other applicable risk-management expectations and legal obligations may still apply. See the OCC revised guidance.
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Neither jurisdictional example is a global rule. Map the use case, legal entity, geography, customer impact, provider role, data, and action authority to the requirements and risk processes that apply to the institution.
How to evaluate a deployment or platform
Use these decision axes to compare architectures and providers; they are not a published ranking.
- Identity and authorization: Can access be integrated with institutional identities and scoped to individual tools, resources, tasks, and environments?
- Action governance: Can read and write capabilities be separated, with approvals and limits applied to consequential actions?
- Data handling: Are classification, residency, retention, and logging requirements supported and verifiable?
- Task behavior: Does the design handle asynchronous or long-running tasks, timeouts, partial results, and duplicate requests safely?
- Evidence and response: Can operators trace actions, decisions, approvals, and failures and respond to incidents?
- Interoperability: Which protocol and SDK versions are supported, and how are compatibility changes tested?
- Provider risk: Are subcontractors, provider concentration, portability, audit rights, continuity, and exit arrangements acceptable?
- Resilience: What are the latency, outage, recovery, and fallback behaviors for each dependency?
A managed service may provide useful infrastructure, but the institution still needs to verify its capabilities, data handling, residency, subcontractors, resilience, audit rights, and exit terms against the relevant jurisdiction and use case. A product or protocol does not make an implementation compliant on its own.
Quick Recap
Common implementation mistakes
- Using MCP and A2A as synonyms: They address different connections. Choose the protocol based on whether the interaction is agent-to-capability or agent-to-agent.
- Treating discovery as trust: A published capability or Agent Card is not authorization. Validate identity, scope, and task permissions independently.
- Assuming the connection carries identity or state: MCP’s stateless request model and transport-specific authorization make explicit application state and identity controls essential.
- Giving a pilot production write access too early: Begin with bounded access and demonstrate control evidence before enabling actions that alter records or affect customers.
- Equating protocol conformance with governance: Interoperability does not establish safe model behavior, appropriate third-party oversight, or regulatory compliance.
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