diff --git a/CHANGELOG.md b/CHANGELOG.md
index 66b1a0b..ffe949f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,42 @@
 # Changelog
 
+## 0.4.1
+
+This patch release synchronizes the public installation documentation with the
+current package line.
+
+### Changed
+
+- Updated repository, SDK, runtime, quickstart, and CI installation examples.
+- Clarified that Streamable HTTP agents and their clients run in separate terminals.
+
+## 0.4.0
+
+This release establishes a stricter, backward-compatible protocol contract and adds
+first-class support for async Python agents.
+
+### Added
+
+- Added method-specific conformance validation for initialize, step, and reset responses.
+- Added machine-readable conformance reports with `--json` and `--json-out`.
+- Added synchronous and asynchronous `@on_step` and `@on_reset` support across stdio
+  and Streamable HTTP.
+- Added configurable RPC timeouts through `--timeout` and `ECP_RPC_TIMEOUT`.
+- Added a runnable async Python example covering both supported transports.
+- Expanded automated test coverage across Python 3.9 through 3.13.
+
+### Changed
+
+- Aligned runtime models, SDK result normalization, JSON Schemas, and protocol validation.
+- Enforced JSON-RPC response identifier matching and preserved evaluator-visible logs.
+- Improved timeout and RPC failure diagnostics with method, scenario, and step context.
+
+### Compatibility
+
+- Existing valid synchronous agents remain supported without migration.
+- Invalid manifests and malformed protocol payloads that previously passed through are
+  now rejected with actionable diagnostics.
+
 ## 0.3.1
 
 This release makes ECP easier to share with developers as a usable portable evaluation contract.
diff --git a/README.md b/README.md
index b1edd56..e69c6d3 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ ECP is a vendor-neutral protocol and reference runtime for testing agent outputs
 
 MCP gives agents a common way to use tools. ECP gives evaluators a common way to inspect what an agent returned, what tools it used, and what audit evidence it exposed.
 
-> Status: experimental but usable. The current package line is `0.3.1`.
+> Status: experimental but usable. The current package line is `0.4.1`.
 
 ## Why ECP
 
@@ -28,7 +28,7 @@ Use ECP when you want to:
 ```bash
 py -m venv .venv
 .\.venv\Scripts\Activate.ps1
-pip install "ecp-runtime==0.3.1" "ecp-sdk==0.3.1"
+pip install "ecp-runtime==0.4.1" "ecp-sdk==0.4.1"
 ecp init
 ecp validate ecp_eval/manifest.yaml
 ecp run --manifest ecp_eval/manifest.yaml --json
diff --git a/docs/ci.md b/docs/ci.md
index 05cf126..6868443 100644
--- a/docs/ci.md
+++ b/docs/ci.md
@@ -20,7 +20,7 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: "3.11"
-      - run: pip install "ecp-runtime==0.3.1" "ecp-sdk==0.3.1"
+      - run: pip install "ecp-runtime==0.4.1" "ecp-sdk==0.4.1"
       - run: ecp validate examples/customer_support_demo/manifest.yaml
       - run: ecp run --manifest examples/customer_support_demo/manifest.yaml --json-out ecp-report.json
       - uses: actions/upload-artifact@v4
diff --git a/docs/examples.md b/docs/examples.md
index dbea5eb..91dcc5e 100644
--- a/docs/examples.md
+++ b/docs/examples.md
@@ -154,10 +154,15 @@ Run it over stdio:
 ecp run --manifest examples/async_python_demo/manifest.yaml --timeout 10
 ```
 
-Or start the same agent over Streamable HTTP:
+Or start the same agent over Streamable HTTP in one terminal:
 
 ```bash
 ECP_TRANSPORT=http ECP_HTTP_PORT=8765 python examples/async_python_demo/agent.py
+```
+
+Run the conformance checks from another terminal:
+
+```bash
 ecp conformance --target http://127.0.0.1:8765/ecp --timeout 10
 ```
 
diff --git a/docs/index.md b/docs/index.md
index f5ee92a..55c96b8 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -36,7 +36,7 @@ Most evals start with the final answer. ECP also checks the behavior behind that
 ## Developer Path
 
 ```bash
-pip install "ecp-runtime==0.3.1" "ecp-sdk==0.3.1"
+pip install "ecp-runtime==0.4.1" "ecp-sdk==0.4.1"
 ecp init
 ecp validate ecp_eval/manifest.yaml
 ecp run --manifest ecp_eval/manifest.yaml --json
diff --git a/docs/quickstart.md b/docs/quickstart.md
index caca434..11f3b84 100644
--- a/docs/quickstart.md
+++ b/docs/quickstart.md
@@ -7,16 +7,16 @@
 ```bash
 py -m venv .venv
 .\.venv\Scripts\Activate.ps1
-pip install "ecp-runtime==0.3.1" "ecp-sdk==0.3.1"
+pip install "ecp-runtime==0.4.1" "ecp-sdk==0.4.1"
 ```
 
 For framework demos, install the matching SDK extra:
 
 ```bash
-pip install "ecp-sdk[langchain]==0.3.1" langchain-openai
-pip install "ecp-sdk[crewai]==0.3.1" crewai
-pip install "ecp-sdk[pydanticai]==0.3.1" pydantic-ai
-pip install "ecp-sdk[llamaindex]==0.3.1" llama-index llama-index-llms-openai llama-index-tools-yahoo-finance
+pip install "ecp-sdk[langchain]==0.4.1" langchain-openai
+pip install "ecp-sdk[crewai]==0.4.1" crewai
+pip install "ecp-sdk[pydanticai]==0.4.1" pydantic-ai
+pip install "ecp-sdk[llamaindex]==0.4.1" llama-index llama-index-llms-openai llama-index-tools-yahoo-finance
 ```
 
 ## 2. Create A Starter Eval
@@ -115,7 +115,7 @@ ecp conformance --target "python agent.py" --timeout 60
 
 ## Notes
 
-- The current release line is `0.3.1`.
+- The current release line is `0.4.1`.
 - New agents should use `evaluation_context`; `private_thought` remains a deprecated compatibility alias.
 - `--timeout` controls the RPC timeout for `run` and `conformance`. It overrides `ECP_RPC_TIMEOUT`; the default is 30 seconds.
 - Python SDK `@on_step` and `@on_reset` hooks may be synchronous or `async def` functions.
diff --git a/sdk/python/README.md b/sdk/python/README.md
index cfbe58a..ac264b1 100644
--- a/sdk/python/README.md
+++ b/sdk/python/README.md
@@ -7,16 +7,16 @@ ECP is a vendor-neutral protocol for testing agent outputs, tool calls, and eval
 ## Install
 
 ```bash
-pip install "ecp-sdk==0.3.1"
+pip install "ecp-sdk==0.4.1"
 ```
 
 Framework extras:
 
 ```bash
-pip install "ecp-sdk[langchain]==0.3.1"
-pip install "ecp-sdk[crewai]==0.3.1"
-pip install "ecp-sdk[llamaindex]==0.3.1"
-pip install "ecp-sdk[pydanticai]==0.3.1"
+pip install "ecp-sdk[langchain]==0.4.1"
+pip install "ecp-sdk[crewai]==0.4.1"
+pip install "ecp-sdk[llamaindex]==0.4.1"
+pip install "ecp-sdk[pydanticai]==0.4.1"
 ```
 
 ## Usage