diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6bfab0255..c427b892e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ Changed `wf10_batch.robot` to be less likely to create files, and
 `plan_generation_graph.robot` to give more test answers.
 
 ## [Unreleased]
+- **docs(a2a): ACP to A2A migration guide** (#10230): Added migration guide documenting how to upgrade from the ACP module to the A2A module introduced in v3.6.0, including symbol renames, field renames, operation-name mappings, and YAML configuration updates.
 - **Plan Prompt JSON Timing Field** (#9353): `agents plan prompt --format json` now
   includes `timing.started` as an ISO 8601 UTC timestamp in the JSON envelope,
   matching the spec (§CLI Commands — `agents plan prompt`). Extended
diff --git a/docs/api/a2a.md b/docs/api/a2a.md
index 8e1ca9211..9cb9e1040 100644
--- a/docs/api/a2a.md
+++ b/docs/api/a2a.md
@@ -134,3 +134,38 @@ config = ServerConnectionConfig(url="https://my-server.example.com", token="..."
 ```
 
 Validates URL format and token presence.
+
+---
+
+## ACP to A2A Rename (v3.6.0)
+
+> **Breaking change in v3.6.0.** The `cleveragents.acp` module was renamed to
+> `cleveragents.a2a`. All `Acp*` class names were renamed to `A2a*`. The
+> `AcpRequest` and `AcpResponse` field names were updated to comply with the
+> JSON-RPC 2.0 specification.
+
+For the complete migration guide, see
+[`docs/development/acp-to-a2a-migration.md`](../development/acp-to-a2a-migration.md).
+
+**Symbol rename summary:**
+
+| Old (ACP) | New (A2A) |
+|---|---|
+| `AcpRequest` | `A2aRequest` |
+| `AcpResponse` | `A2aResponse` |
+| `AcpLocalFacade` | `A2aLocalFacade` |
+| `AcpError` | `A2aError` |
+| `AcpEventQueue` | `A2aEventQueue` |
+
+**Field rename summary (`A2aRequest` / `A2aResponse`):**
+
+| Old Field | New Field |
+|---|---|
+| `a2a_version` | `jsonrpc` |
+| `request_id` | `id` |
+| `operation` | `method` |
+| `payload` | `params` |
+| `data` | `result` |
+| `error_detail` | `error` |
+
+See [ADR-047](../adr/ADR-047-acp-standard-adoption.md) for architectural rationale.
diff --git a/docs/development/acp-to-a2a-migration.md b/docs/development/acp-to-a2a-migration.md
new file mode 100644
index 000000000..30022bec3
--- /dev/null
+++ b/docs/development/acp-to-a2a-migration.md
@@ -0,0 +1,264 @@
+# ACP to A2A Module Rename and Symbol Standardization
+
+> **Introduced in:** v3.6.0
+> **Architectural decision:** [ADR-047 - A2A Standard Adoption](../adr/ADR-047-acp-standard-adoption.md)
+> **Module path:** `cleveragents.a2a` (commit `449c33b7`)
+
+---
+
+## Overview
+
+In v3.6.0 the internal **ACP (Agent Client Protocol)** module was renamed to
+**A2A (Agent-to-Agent Protocol)** and all public symbols were standardized to
+align with the external [A2A open standard](https://a2a-protocol.org) (Linux
+Foundation, Apache 2.0).
+
+This was not merely a rename - it was an architectural shift from a bespoke
+JSON envelope protocol to the industry-standard A2A wire format built on
+**JSON-RPC 2.0**. The change eliminates the proprietary ACP envelope, replaces
+custom REST routing with JSON-RPC 2.0 method dispatch, and introduces
+**Agent Card** discovery (`/.well-known/agent.json`).
+
+---
+
+## What Changed
+
+### 1. Module Path
+
+| Before (ACP) | After (A2A) |
+|---|---|
+| `cleveragents.acp` | `cleveragents.a2a` |
+| `from cleveragents.acp import ...` | `from cleveragents.a2a import ...` |
+
+### 2. Class and Symbol Names
+
+All public symbols were renamed from `Acp*` to `A2a*`:
+
+| Old Symbol (ACP) | New Symbol (A2A) | Notes |
+|---|---|---|
+| `AcpRequest` | `A2aRequest` | Wire format changed - see section 3 |
+| `AcpResponse` | `A2aResponse` | Wire format changed - see section 3 |
+| `AcpError` | `A2aError` | Base exception |
+| `AcpNotAvailableError` | `A2aNotAvailableError` | Server-mode guard |
+| `AcpOperationNotFoundError` | `A2aOperationNotFoundError` | Unknown method |
+| `AcpVersionMismatchError` | `A2aVersionMismatchError` | Protocol version guard |
+| `AcpLocalFacade` | `A2aLocalFacade` | Local-mode dispatcher |
+| `AcpHttpTransport` | `A2aHttpTransport` | Server-mode transport stub |
+| `AcpEventQueue` | `A2aEventQueue` | In-process event delivery |
+| `AcpVersionNegotiator` | `A2aVersionNegotiator` | Version negotiation |
+| `AcpVersion` | `A2aVersion` | Version constants |
+| `AcpEvent` | `A2aEvent` | SSE event envelope |
+| `AcpErrorDetail` | `A2aErrorDetail` | JSON-RPC error object |
+
+### 3. Request and Response Field Names
+
+`A2aRequest` and `A2aResponse` now use **JSON-RPC 2.0** field names instead of
+the proprietary ACP envelope fields. These models are defined in
+`cleveragents.a2a.models` (commit `449c33b7`):
+
+| Old Field (ACP) | New Field (A2A / JSON-RPC 2.0) | Type |
+|---|---|---|
+| `a2a_version` | `jsonrpc` (always `"2.0"`) | `str` |
+| `request_id` | `id` | `str` |
+| `operation` | `method` | `str` |
+| `payload` | `params` | `dict[str, Any]` |
+| `data` (success path) | `result` | `dict[str, Any] or None` |
+| `error_detail` | `error` | `A2aErrorDetail or None` |
+
+**Before (ACP):**
+```python
+from cleveragents.acp import AcpRequest, AcpLocalFacade
+
+request = AcpRequest(
+    a2a_version="1.0",
+    request_id="req-001",
+    operation="plan.status",
+    payload={"plan_id": "01HXRCF1..."},
+)
+response = facade.dispatch(request)
+if response.data:
+    print(response.data["phase"])
+```
+
+**After (A2A):**
+```python
+from cleveragents.a2a import A2aRequest, A2aLocalFacade
+
+request = A2aRequest(
+    jsonrpc="2.0",
+    id="req-001",
+    method="_cleveragents/plan/status",
+    params={"plan_id": "01HXRCF1..."},
+)
+response = facade.dispatch(request)
+if response.result:
+    print(response.result["phase"])
+```
+
+### 4. Operation Names
+
+The ACP proprietary operation names were replaced with the A2A standard
+`_cleveragents/` extension method namespace. The legacy names are still
+accepted by `A2aLocalFacade.dispatch()` in `cleveragents.a2a.facade`
+(commit `449c33b7`) for backward compatibility but are **deprecated** and
+will be removed in a future major version.
+
+| Old Operation (ACP / deprecated) | New Operation (A2A) |
+|---|---|
+| `session.create` | `_cleveragents/session/create` (via `message/send`) |
+| `session.close` | `_cleveragents/session/close` |
+| `plan.create` | `_cleveragents/plan/use` |
+| `plan.execute` | `_cleveragents/plan/execute` |
+| `plan.status` | `_cleveragents/plan/status` |
+| `plan.diff` | `_cleveragents/plan/diff` |
+| `plan.apply` | `_cleveragents/plan/apply` |
+| `registry.list_tools` | `_cleveragents/registry/tool/list` |
+| `registry.list_resources` | `_cleveragents/registry/resource/list` |
+| `context.get` | `_cleveragents/context/show` |
+| `event.subscribe` | (event delivery via SSE `message/stream`) |
+
+The full list of supported A2A extension methods is documented in
+[`docs/reference/a2a.md`](../reference/a2a.md#extension-methods).
+
+### 5. YAML and Configuration Files
+
+If you have YAML configuration files, actor definitions, or skill files that
+reference the old ACP module path or operation names, update them as follows:
+
+**Actor YAML - protocol binding:**
+```yaml
+# Before (ACP)
+protocol:
+  type: acp
+  version: "1.0"
+
+# After (A2A)
+protocol:
+  type: a2a
+  version: "2.0"
+```
+
+**Skill YAML - operation references:**
+```yaml
+# Before (ACP)
+operations:
+  - operation: plan.create
+  - operation: plan.execute
+
+# After (A2A)
+operations:
+  - method: _cleveragents/plan/use
+  - method: _cleveragents/plan/execute
+```
+
+**Server connection config:**
+```yaml
+# Before (ACP)
+server:
+  protocol: acp
+  endpoint: https://my-server.example.com/acp
+
+# After (A2A)
+server:
+  protocol: a2a
+  endpoint: https://my-server.example.com/a2a
+```
+
+---
+
+## Migration Steps
+
+Follow these steps when upgrading from a codebase that used the ACP module:
+
+### Step 1 - Update imports
+
+Replace all `cleveragents.acp` imports with `cleveragents.a2a`:
+
+```bash
+# Find all files that import from the old ACP module
+grep -r "from cleveragents.acp" src/ tests/
+grep -r "import cleveragents.acp" src/ tests/
+```
+
+Then update each import:
+```python
+# Before
+from cleveragents.acp import AcpLocalFacade, AcpRequest, AcpResponse
+
+# After
+from cleveragents.a2a import A2aLocalFacade, A2aRequest, A2aResponse
+```
+
+### Step 2 - Rename symbol references
+
+Use your editor's find-and-replace to rename all `Acp*` symbols to `A2a*`
+(see the complete symbol table in section 2 above).
+
+### Step 3 - Update request field names
+
+Update all `AcpRequest` and `AcpResponse` constructor calls and field accesses
+to use the new JSON-RPC 2.0 field names (see section 3 above).
+
+### Step 4 - Update operation names
+
+Replace deprecated ACP operation strings with the new `_cleveragents/`
+extension method names (see section 4 above). The legacy names still work but
+emit deprecation warnings.
+
+### Step 5 - Update YAML files
+
+Search for any YAML files that reference `acp` in protocol type fields or
+operation names and update them (see section 5 above).
+
+### Step 6 - Verify
+
+Run the full test suite to confirm no regressions:
+
+```bash
+nox -s unit_tests
+nox -s integration_tests
+```
+
+---
+
+## Backward Compatibility
+
+The `A2aLocalFacade.dispatch()` method in `cleveragents.a2a.facade.A2aLocalFacade`
+(commit `449c33b7`) continues to accept the legacy ACP operation names
+(`session.create`, `plan.create`, etc.) via the `_LEGACY_OPERATIONS` list.
+This backward compatibility shim will be removed in the next major version.
+
+The `A2aVersion` class in `cleveragents.a2a.models.A2aVersion` (commit
+`449c33b7`) retains the `CURRENT` and `SUPPORTED` constants for backward
+compatibility, though the wire format now uses the `jsonrpc` field rather than
+a proprietary `a2a_version` field.
+
+---
+
+## Architectural Rationale
+
+The rename was driven by the adoption of the external A2A open standard
+([a2a-protocol.org](https://a2a-protocol.org)), which supersedes the bespoke
+ACP protocol. Key reasons for the change:
+
+- **Ecosystem alignment**: A2A is governed by the Linux Foundation with 22k+
+  GitHub stars and SDKs in Python, Go, JavaScript, Java, and .NET.
+- **Agent Card discovery**: The standard introduces `/.well-known/agent.json`
+  for dynamic capability advertisement.
+- **JSON-RPC 2.0**: Replaces the proprietary envelope with a mature, widely-
+  tooled standard.
+- **Extensibility**: The `_cleveragents/` extension namespace cleanly separates
+  platform-specific operations from standard agent interactions.
+
+See [ADR-047](../adr/ADR-047-acp-standard-adoption.md) for the full
+architectural rationale and decision record.
+
+---
+
+## Related Documentation
+
+- [A2A Reference](../reference/a2a.md) - complete API reference for the `cleveragents.a2a` module
+- [A2A API](../api/a2a.md) - class-level API documentation
+- [ADR-026 - Agent-to-Agent Protocol](../adr/ADR-026-agent-client-protocol.md) - protocol boundary design
+- [ADR-047 - A2A Standard Adoption](../adr/ADR-047-acp-standard-adoption.md) - rationale for adopting the external standard
+- [ADR-048 - Server Application Architecture](../adr/ADR-048-server-application-architecture.md) - server implementation using A2A
diff --git a/docs/reference/a2a.md b/docs/reference/a2a.md
index 23ff95a0e..a0d9ab41d 100644
--- a/docs/reference/a2a.md
+++ b/docs/reference/a2a.md
@@ -88,8 +88,8 @@ via the `getExtendedAgentCard` operation.
 
 ## Transport Modes
 
-| Mode   | Transport              | Class / SDK Component              | Behaviour                                                          |
-|--------|------------------------|------------------------------------|--------------------------------------------------------------------|
+| Mode   | Transport              | Class / SDK Component              | Behaviour                                              |
+|--------|------------------------|------------------------------------|--------------------------------------------------------|
 | Local  | A2A JSON-RPC over stdio | `A2aLocalFacade` + JSON-RPC stdio  | Agent as subprocess; extensions resolved in-process |
 | Server | A2A JSON-RPC over HTTP  | A2A SDK HTTP transport             | JSON-RPC 2.0 to CleverAgents server               |
 
@@ -165,7 +165,7 @@ Pattern applies to all entity types (`actor`, `skill`, `tool`, `validation`,
 ### Context Operations
 
 | Method | Service Method | Required Params |
-|--------|----------------|-----------------|
+|--------|---------------|-----------------|
 | `_cleveragents/context/show` | `ContextService.show()` | `project_name` |
 | `_cleveragents/context/inspect` | `ContextService.inspect()` | `project_name` |
 | `_cleveragents/context/simulate` | `ContextService.simulate()` | `project_name`, simulation params |
@@ -174,7 +174,7 @@ Pattern applies to all entity types (`actor`, `skill`, `tool`, `validation`,
 ### Sync Operations
 
 | Method | Service Method | Required Params |
-|--------|----------------|-----------------|
+|--------|---------------|-----------------|
 | `_cleveragents/sync/pull` | `SyncService.pull()` | `namespace` |
 | `_cleveragents/sync/push` | `SyncService.push()` | `namespace`, `entities` |
 | `_cleveragents/sync/status` | `SyncService.status()` | `namespace` (optional) |
@@ -182,7 +182,7 @@ Pattern applies to all entity types (`actor`, `skill`, `tool`, `validation`,
 ### Namespace Operations
 
 | Method | Service Method | Required Params |
-|--------|----------------|-----------------|
+|--------|---------------|-----------------|
 | `_cleveragents/namespace/list` | `NamespaceService.list()` | -- |
 | `_cleveragents/namespace/show` | `NamespaceService.show()` | `namespace` |
 | `_cleveragents/namespace/members` | `NamespaceService.members()` | `namespace` |
@@ -198,20 +198,13 @@ Pattern applies to all entity types (`actor`, `skill`, `tool`, `validation`,
 
 ## Streaming Events
 
-A2A streaming uses SSE via the `message/stream` operation (client → server
-request), delivering typed events as the task progresses. The SSE data
-payloads are JSON-RPC 2.0 **notifications** (no `id` field):
+A2A streaming uses SSE via the `message/stream` operation, delivering typed
+events as the task progresses:
 
-| Event Type | JSON-RPC Method | Emitted When |
-|------------|-----------------|--------------|
-| `TaskStatusUpdateEvent` | `task/statusUpdate` | Task state changes (submitted -> working -> completed, etc.) |
-| `TaskArtifactUpdateEvent` | `task/artifactUpdate` | Agent produces output (response chunks, plan entries, tool results) |
-
-> **Note:** `message/stream` is the **request** method (client → server) that
-> initiates streaming. The SSE data payloads use `task/statusUpdate` or
-> `task/artifactUpdate` as the notification method name — not `message/stream`.
-> Non-spec fields (`event_id`, `event_type`, `timestamp`) are carried in SSE
-> envelope headers (`event:` and `id:` lines), not in the data payload.
+| Event Type | Emitted When |
+|-----------|-------------|
+| `TaskStatusUpdateEvent` | Task state changes (submitted -> working -> completed, etc.) |
+| `TaskArtifactUpdateEvent` | Agent produces output (response chunks, plan entries, tool results) |
 
 ### Task Lifecycle States
 
@@ -227,30 +220,16 @@ payloads are JSON-RPC 2.0 **notifications** (no `id` field):
 
 ### Example Streaming Event
 
-SSE data payload for a task status update (JSON-RPC 2.0 notification):
-
 ```json
 {
   "jsonrpc": "2.0",
-  "method": "task/statusUpdate",
+  "method": "message/stream",
   "params": {
-    "taskId": "task_01HXR...",
-    "status": { "state": "working" }
-  }
-}
-```
-
-SSE data payload for an artifact update:
-
-```json
-{
-  "jsonrpc": "2.0",
-  "method": "task/artifactUpdate",
-  "params": {
-    "taskId": "task_01HXR...",
-    "artifact": {
+    "id": "task_01HXR...",
+    "status": { "state": "working" },
+    "artifacts": [{
       "parts": [{ "text": "I'll start by extracting..." }]
-    }
+    }]
   }
 }
 ```
@@ -298,9 +277,9 @@ response = facade.dispatch(A2aRequest(
 
 ### Constructor
 
-| Parameter  | Type                             | Default | Description                    |
-|------------|----------------------------------|---------|--------------------------------|
-| `services` | `dict[str, Any] \| None`   | `None`  | Named services for routing     |
+| Parameter  | Type                       | Default | Description                   |
+|------------|----------------------------|---------|-------------------------------|
+| `services` | `dict[str, Any] \| None`   | `None`  | Named services for routing    |
 
 ### Methods
 
@@ -320,15 +299,15 @@ registered later with `register_service()`.
 
 ### Service Keys
 
-| Key                              | Type                             | Wired Methods                              |
-|----------------------------------|----------------------------------|--------------------------------------------|
-| `session_service`                | `SessionWorkflow`                | Standard message operations                |
-| `plan_lifecycle_service`         | `PlanLifecycleService`           | `_cleveragents/plan/*`                     |
-| `tool_registry`                  | `ToolRegistry`                   | `_cleveragents/registry/tool/*`            |
-| `resource_registry_service`      | `ResourceRegistryService`        | `_cleveragents/registry/resource/*`        |
-| `sync_service`                   | `SyncService`                    | `_cleveragents/sync/*`                     |
-| `namespace_service`              | `NamespaceService`               | `_cleveragents/namespace/*`                |
-| `context_service`                | `ContextService`                 | `_cleveragents/context/*`                  |
+| Key                          | Type                        | Wired Methods                       |
+|------------------------------|-----------------------------|-------------------------------------|
+| `session_service`            | `SessionWorkflow`           | Standard message operations         |
+| `plan_lifecycle_service`     | `PlanLifecycleService`      | `_cleveragents/plan/*`              |
+| `tool_registry`              | `ToolRegistry`              | `_cleveragents/registry/tool/*`     |
+| `resource_registry_service`  | `ResourceRegistryService`   | `_cleveragents/registry/resource/*` |
+| `sync_service`               | `SyncService`               | `_cleveragents/sync/*`              |
+| `namespace_service`          | `NamespaceService`          | `_cleveragents/namespace/*`         |
+| `context_service`            | `ContextService`            | `_cleveragents/context/*`           |
 
 ---
 
@@ -423,8 +402,42 @@ CleverAgentsError
         └── A2aOperationNotFoundError
 ```
 
-| Exception                    | When Raised                                                        |
-|------------------------------|--------------------------------------------------------------------|
-| `A2aNotAvailableError`       | Server-mode operation attempted without connection |
-| `A2aVersionMismatchError`    | Unsupported A2A version                                            |
-| `A2aOperationNotFoundError`  | Unknown method dispatched                                          |
+| Exception                   | When Raised                                        |
+|-----------------------------|----------------------------------------------------|
+| `A2aNotAvailableError`      | Server-mode operation attempted without connection |
+| `A2aVersionMismatchError`   | Unsupported A2A version                            |
+| `A2aOperationNotFoundError` | Unknown method dispatched                          |
+
+---
+
+## ACP to A2A Migration
+
+> **v3.6.0 breaking change.** The `cleveragents.acp` module was renamed to
+> `cleveragents.a2a` and all `Acp*` symbols were renamed to `A2a*`. The
+> request/response wire format was updated to comply with JSON-RPC 2.0.
+
+For a complete migration guide including symbol rename tables, field name
+changes, operation name mapping, and YAML configuration updates, see
+[`docs/development/acp-to-a2a-migration.md`](../development/acp-to-a2a-migration.md).
+
+### Quick Reference: Deprecated Legacy Operations
+
+The following ACP operation names are accepted by `A2aLocalFacade.dispatch()`
+in `cleveragents.a2a.facade.A2aLocalFacade` (commit `449c33b7`) for backward
+compatibility but are **deprecated**:
+
+| Deprecated (ACP) | Replacement (A2A) |
+|---|---|
+| `session.create` | `_cleveragents/session/create` |
+| `session.close` | `_cleveragents/session/close` |
+| `plan.create` | `_cleveragents/plan/use` |
+| `plan.execute` | `_cleveragents/plan/execute` |
+| `plan.status` | `_cleveragents/plan/status` |
+| `plan.diff` | `_cleveragents/plan/diff` |
+| `plan.apply` | `_cleveragents/plan/apply` |
+| `registry.list_tools` | `_cleveragents/registry/tool/list` |
+| `registry.list_resources` | `_cleveragents/registry/resource/list` |
+| `context.get` | `_cleveragents/context/show` |
+
+See [ADR-047](../adr/ADR-047-acp-standard-adoption.md) for the architectural
+rationale behind this change.
diff --git a/mkdocs.yml b/mkdocs.yml
index fc4864bad..107028bcf 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -52,6 +52,7 @@ nav:
     - Automation Tracking: development/automation-tracking.md
     - Custom Sandbox Strategy: development/custom_sandbox_strategy.md
     - Documentation Writer: development/docs-writer.md
+    - ACP to A2A Migration: development/acp-to-a2a-migration.md
   - Implementation Timeline: timeline.md
   - Advanced Concepts (v3.6.0):
     - Overview & Context Strategies: advanced-concepts/index.md