diff --git a/CHANGELOG.md b/CHANGELOG.md
index dc93738..0c1a25e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.17.0] — 2026-08-26
+
 ### Added
 
 - **Real per-turn token and cost usage, on the envelope and on both wrapper SDKs.**
@@ -59,15 +61,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   engine on `0.4.0` fail the handshake loudly (`protocol_version_mismatch`) rather than silently
   misbehaving, so **upgrading the engine and both wrapper packages together is required.**
 
-### Fixed
-
-- **The wrapper's `stderr_tail` cap now measures real UTF-8 bytes, not characters.** It previously
-  sliced a plain string, so on non-ASCII stderr the cap was wrong by roughly the size of the
-  encoding (a Japanese reply could overshoot a byte budget several times over). The cap is now
-  byte-accurate and never splits a codepoint, which means it may return a handful of bytes fewer
-  than the requested cap when trimming lands mid-character. The exported `STDERR_TAIL_BYTES`
-  constant keeps its name and its value (4096); it simply counts the right unit now.
-
 - **`amplifier-agent run --prompt-file <path>`,** a second transport for the prompt. The
   positional `PROMPT` argument remains valid and unchanged; the two are mutually exclusive.
   File contents are decoded as UTF-8 and delivered verbatim, with no stripping and no newline
@@ -82,6 +75,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **The wrapper's `stderr_tail` cap now measures real UTF-8 bytes, not characters.** It previously
+  sliced a plain string, so on non-ASCII stderr the cap was wrong by roughly the size of the
+  encoding (a Japanese reply could overshoot a byte budget several times over). The cap is now
+  byte-accurate and never splits a codepoint, which means it may return a handful of bytes fewer
+  than the requested cap when trimming lands mid-character. The exported `STDERR_TAIL_BYTES`
+  constant keeps its name and its value (4096); it simply counts the right unit now.
+
 - **Wrappers now emit `--` before the positional prompt.** A prompt beginning with `-` was
   parsed as an option, so the turn died with exit 2 and `No such option` before the engine
   booted. The separator is emitted unconditionally rather than only for `-`-leading prompts.
@@ -97,6 +97,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   fail to decode, and the reader turns a decode failure into a warning and reports no configured
   servers. The TypeScript wrapper was already correct.
 
+### Notes
+
+- **This is a coordinated release. Upgrade the engine and the TypeScript SDK together.**
+  `amplifier-agent` moves to `0.17.0` and `amplifier-agent-ts` to `0.8.0`. Because
+  `PROTOCOL_VERSION` moved `0.3.0` -> `0.4.0`, an `amplifier-agent-ts` still on `0.7.1` will
+  refuse an engine on `0.17.0` with `protocol_version_mismatch`, and the reverse holds too. The
+  refusal is deliberate and loud; there is no silent-degradation path to fall back on.
+
+- **The Python SDK changes described above are on `main` but are not yet published.**
+  `amplifier-agent-py` has never had a release, so it is not part of this one. Its source already
+  carries the `0.4.0` protocol pin and the prompt-spill and MCP-encoding fixes; they reach
+  consumers with that package's first release.
+
 ## [0.16.0] — 2026-08-25
 
 ### Changed
diff --git a/README.md b/README.md
index e80f304..897d54e 100644
--- a/README.md
+++ b/README.md
@@ -136,7 +136,7 @@ Host Application                              ← your code
        amplifier-agent CLI  /  HTTP face         │   ← this repo
        (argv in, JSON envelope out)              │
            ↓                                     │
-    ┌──────────────────────────────────────────┘
+    ┌────────────────────────────────────────────┘
     ↓
 amplifier_agent_lib (the engine)              ← this repo
 ```
diff --git a/pyproject.toml b/pyproject.toml
index 5a385e4..f7cf372 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = 'amplifier-agent'
-version = '0.16.0'
+version = '0.17.0'
 requires-python = '>=3.12'
 license = 'MIT'
 dependencies = [
diff --git a/uv.lock b/uv.lock
index 3edf683..d91b063 100644
--- a/uv.lock
+++ b/uv.lock
@@ -16,7 +16,7 @@ members = [
 
 [[package]]
 name = "amplifier-agent"
-version = "0.16.0"
+version = "0.17.0"
 source = { editable = "." }
 dependencies = [
     { name = "amplifier-foundation" },
diff --git a/wrappers/typescript/package.json b/wrappers/typescript/package.json
index 40503e2..a0a341c 100644
--- a/wrappers/typescript/package.json
+++ b/wrappers/typescript/package.json
@@ -1,6 +1,6 @@
 {
   "name": "amplifier-agent-ts",
-  "version": "0.7.1",
+  "version": "0.8.0",
   "description": "TypeScript SDK for the Amplifier agent. Spawns and drives the amplifier-agent Python CLI over a stdio protocol.",
   "type": "module",
   "exports": {