diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
index 0bed27be..c521ce4c 100644
--- a/.claude-plugin/marketplace.json
+++ b/.claude-plugin/marketplace.json
@@ -17,10 +17,6 @@
       "name": "unic-confluence",
       "source": "./apps/claude-code/unic-confluence"
     },
-    {
-      "name": "unic-archon-dlc",
-      "source": "./apps/claude-code/unic-archon-dlc"
-    },
     {
       "name": "unic-pr-review",
       "source": "./apps/claude-code/unic-pr-review"
diff --git a/README.md b/README.md
index a8e35629..bce4da42 100644
--- a/README.md
+++ b/README.md
@@ -9,9 +9,10 @@ A monorepo of AI agent plugins developed at Unic. Currently hosts Claude Code pl
 | [`pr-review`](apps/claude-code/pr-review/)             | Claude Code | Review Azure DevOps pull requests                                                                   |
 | [`auto-format`](apps/claude-code/auto-format/)         | Claude Code | Auto-format and lint files after edits                                                              |
 | [`unic-confluence`](apps/claude-code/unic-confluence/) | Claude Code | Publish Markdown files to Confluence                                                                |
-| [`unic-archon-dlc`](apps/claude-code/unic-archon-dlc/) | Claude Code | Archon-powered AI development lifecycle (explore → plan → build → qa → cleanup → triage)            |
 | [`unic-pr-review`](apps/claude-code/unic-pr-review/)   | Claude Code | AI-powered PR reviews with Atlassian intent checking, confidence-scored findings, and Approval Loop |
 
+The `unic-archon-dlc` plugin was withdrawn from the catalogue on 2026-10-30. See [#677](https://github.com/unic/unic-agents-plugins/issues/677).
+
 ## Installing plugins (Claude Code)
 
 Add the Unic marketplace once (run inside `claude`):
@@ -30,7 +31,6 @@ Then install individual plugins:
 /plugin install pr-review@unic-agent-plugins
 /plugin install auto-format@unic-agent-plugins
 /plugin install unic-confluence@unic-agent-plugins
-/plugin install unic-archon-dlc@unic-agent-plugins
 /plugin install unic-pr-review@unic-agent-plugins
 ```
 
diff --git a/apps/claude-code/unic-archon-dlc/.claude-plugin/plugin.json b/apps/claude-code/unic-archon-dlc/.claude-plugin/plugin.json
index 20e45a28..49c536da 100644
--- a/apps/claude-code/unic-archon-dlc/.claude-plugin/plugin.json
+++ b/apps/claude-code/unic-archon-dlc/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "name": "unic-archon-dlc",
   "version": "0.36.1",
-  "description": "A config-driven Harness for the SDLC — the AI development lifecycle — as an installable Claude Code plugin — main line /specs → /tickets → /build → /pr-review → /qa, plus /triage, /explore, /improve-architecture, and /cleanup. Four Archon workflows (build, qa, pr-review, explore) with human approval gates; the rest are commands/skills composing Matt Pocock's methods.",
+  "description": "[DEPRECATED — being replaced, see #677] A config-driven Harness for the SDLC — the AI development lifecycle — as an installable Claude Code plugin — main line /specs → /tickets → /build → /pr-review → /qa, plus /triage, /explore, /improve-architecture, and /cleanup. Four Archon workflows (build, qa, pr-review, explore) with human approval gates; the rest are commands/skills composing Matt Pocock's methods.",
   "author": {
     "name": "Unic AG",
     "url": "https://www.unic.com"
diff --git a/apps/claude-code/unic-archon-dlc/README.md b/apps/claude-code/unic-archon-dlc/README.md
index ebbe4d98..d66cbcd0 100644
--- a/apps/claude-code/unic-archon-dlc/README.md
+++ b/apps/claude-code/unic-archon-dlc/README.md
@@ -1,5 +1,7 @@
 # unic-archon-dlc
 
+This plugin is deprecated. It was withdrawn from the catalogue on 2026-10-30, and a new plugin will replace it. See [#677](https://github.com/unic/unic-agents-plugins/issues/677).
+
 A config-driven Harness for the **SDLC** — the AI development lifecycle — installable as a Claude Code
 plugin. It is a **Harness** —
 it owns the box set below, plus isolation, gates, config and integrity — and **composes the team's