diff --git a/.devcontainer/backend/Dockerfile b/.devcontainer/backend/Dockerfile
index a92d37f6..983670e4 100644
--- a/.devcontainer/backend/Dockerfile
+++ b/.devcontainer/backend/Dockerfile
@@ -86,10 +86,16 @@ USER ${USER}
 # Bootstrap LazyVim starter config
 RUN git clone https://github.com/LazyVim/starter /home/${USER}/.config/nvim \
     && rm -rf /home/${USER}/.config/nvim/.git
-# Install Claude
+# Install Claude + plugins
 RUN curl -fsSL https://claude.ai/install.sh | bash \
     && export PATH="/home/${USER}/.local/bin:${PATH}" \
     && claude plugin marketplace add JuliusBrussee/caveman \
-    && claude plugin install caveman@caveman
+    && claude plugin install caveman@caveman \
+    && claude plugin marketplace add mattpocock/skills \
+    && claude plugin install skills@grill-me \
+    && claude plugin install skills@to-prd \
+    && claude plugin install skills@ubiquitous-language \
+    && claude plugin install skills@tdd \
+    && claude plugin install skills@improve-codebase-architecture
 ENV PATH="/home/vscode/.local/bin:${PATH}"
 USER root
diff --git a/.devcontainer/backend/install-claude-skills.sh b/.devcontainer/backend/install-claude-skills.sh
new file mode 100755
index 00000000..71727e4d
--- /dev/null
+++ b/.devcontainer/backend/install-claude-skills.sh
@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Run this in an existing container to install the mattpocock skills
+# without rebuilding the image. New containers get them automatically via Dockerfile.
+set -euo pipefail
+
+echo "Installing Claude Code skills (mattpocock/skills)..."
+
+claude plugin marketplace add mattpocock/skills
+claude plugin install skills@grill-me
+claude plugin install skills@to-prd
+claude plugin install skills@ubiquitous-language
+claude plugin install skills@tdd
+claude plugin install skills@improve-codebase-architecture
+
+echo "Done. Available: /grill-me  /to-prd  /ubiquitous-language  /tdd  /improve-codebase-architecture"
diff --git a/CLAUDE.md b/CLAUDE.md
index de2917f2..263679ff 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -28,3 +28,34 @@ You MUST read the overview resource to understand the complete workflow. The inf
 
 <!-- BACKLOG.MD MCP GUIDELINES END -->
 
+## Available Skills
+
+Five Claude Code skills are installed in this repo's dev container. Each maps to a phase of the feature lifecycle.
+
+| Skill | Invoke | When to use |
+|-------|--------|-------------|
+| **grill-me** | `/grill-me` | Before implementing — stress-tests a design through sequential questioning |
+| **to-prd** | `/to-prd` | After a planning conversation — formalises context into a GitHub issue PRD |
+| **ubiquitous-language** | `/ubiquitous-language` | When domain terms are drifting or ambiguous — builds/updates `UBIQUITOUS_LANGUAGE.md` |
+| **tdd** | `/tdd` | During implementation — enforces vertical-slice TDD (one test → one impl → repeat) |
+| **improve-codebase-architecture** | `/improve-codebase-architecture` | During refactoring — surfaces shallow modules and proposes deepening opportunities |
+
+### Typical session chains
+
+**Feature planning:**
+`/grill-me` → `/to-prd` → `/ubiquitous-language`
+
+**Implementation:**
+`/tdd` (+ `/grill-me` if a design fork appears mid-session)
+
+**Refactoring:**
+`/improve-codebase-architecture` → `/grill-me` → `/tdd` → `/ubiquitous-language`
+
+### First time setting up?
+
+New containers install all skills automatically via the Dockerfile. If you're in an existing container, run:
+
+```bash
+bash .devcontainer/backend/install-claude-skills.sh
+```
+
diff --git a/UBIQUITOUS_LANGUAGE.md b/UBIQUITOUS_LANGUAGE.md
new file mode 100644
index 00000000..3f2c3fe3
--- /dev/null
+++ b/UBIQUITOUS_LANGUAGE.md
@@ -0,0 +1,9 @@
+# Ubiquitous Language
+
+Domain terminology glossary for this project. Generated and maintained by the `/ubiquitous-language` Claude Code skill.
+
+Invoke `/ubiquitous-language` in any session to extract new terms from the conversation, flag ambiguities, and update this file with canonical definitions.
+
+---
+
+<!-- Terms will be written here by the /ubiquitous-language skill -->