Add MarkItDown skill for OpenChamber workflows

Seed a markitdown converter skill, command, and instruction into ~/.opencode at startup, install uv/markitdown automatically, and support both explicit /to-markdown calls and natural-language routing.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: GitHub Copilot CLI

.devcontainer/opencode-seed/commands/to-markdown.md

@@ -0,0 +1,26 @@
+---
+description: Convert files/URLs to Markdown via MarkItDown
+agent: build
+---
+
+# to-markdown
+
+Convert source content into Markdown using MarkItDown.
+
+## Usage
+
+`/to-markdown <input-path-or-url> [output.md]`
+
+## Execution
+
+1. Parse `$ARGUMENTS` as:
+   - first token: input path or URL
+   - optional second token: output file path
+2. Run:
+
+```bash
+bash /home/vscode/.opencode/skills/markitdown-converter/scripts/convert.sh <input> [output]
+```
+
+3. If output path is provided, report the saved path.
+4. If output path is omitted, return the generated Markdown in the response.

.devcontainer/opencode-seed/instructions/markitdown-converter.md

@@ -0,0 +1,6 @@
+When users ask to read, summarize, or analyze non-Markdown sources (PDF, DOCX, PPTX, HTML, image-derived text, or URLs), first convert the source with `/to-markdown`.
+
+Guidelines:
+- Prefer `/to-markdown <input> <output.md>` for large inputs.
+- For small inputs, `/to-markdown <input>` and return inline Markdown is acceptable.
+- After conversion, continue analysis using the Markdown output only.

.devcontainer/opencode-seed/skills/markitdown-converter/SKILL.md

@@ -0,0 +1,27 @@
+---
+name: markitdown-converter
+description: Convert files and URLs into Markdown so AI agents can reliably read and reason over mixed-format content.
+origin: opencode-ecc-devcontainer
+---
+
+# MarkItDown Converter
+
+Use this skill when you need to transform non-Markdown sources (PDF, Office docs, HTML, images with OCR-capable inputs, etc.) into Markdown before analysis.
+
+## When to Activate
+
+- User asks to summarize or extract data from files that are not already Markdown
+- User provides URLs or documents that should be converted for downstream AI workflows
+- You need a consistent Markdown representation before chunking, indexing, or prompt injection checks
+
+## OpenChamber Usage
+
+1. Explicit command:
+   - `/to-markdown <input> [output.md]`
+2. Natural language:
+   - Ask normally (e.g. "このPDFをMarkdown化して"), then route through `/to-markdown`
+
+## Notes
+
+- If output is large, prefer writing to a file and then summarizing key sections.
+- Preserve the generated Markdown as an artifact when reproducibility is needed.

.devcontainer/opencode-seed/skills/markitdown-converter/scripts/convert.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [ "$#" -lt 1 ]; then
+  echo "Usage: convert.sh <input-path-or-url> [output.md]" >&2
+  exit 1
+fi
+
+INPUT="$1"
+OUTPUT="${2:-}"
+
+if ! command -v markitdown >/dev/null 2>&1; then
+  echo "markitdown is not installed. Install with: uv tool install markitdown" >&2
+  exit 2
+fi
+
+if [ -n "$OUTPUT" ]; then
+  markitdown "$INPUT" > "$OUTPUT"
+  echo "Saved Markdown: $OUTPUT"
+else
+  markitdown "$INPUT"
+fi

.devcontainer/setup.sh

@@ -91,6 +91,19 @@ if [ ${#INSTALL_PIDS[@]} -gt 0 ]; then
     done
 fi
 
+# Pythonツール管理用 uv の準備
+if ! command -v uv &> /dev/null; then
+    echo "🐍 uv をインストール中..."
+    if curl -LsSf https://astral.sh/uv/install.sh | sh; then
+        export PATH="/home/vscode/.local/bin:$PATH"
+        echo "   ✅ uv インストール完了"
+    else
+        echo "   ⚠️  uv インストールに失敗しました（後で手動インストールしてください）"
+    fi
+else
+    echo "   ✅ uv 既にインストール済み: $(uv --version 2>/dev/null || echo 'version unknown')"
+fi
+
 # ECC の設定適用
 echo "   ECC設定を適用中..."
 

.devcontainer/startup.sh

@@ -177,6 +177,64 @@ else
     echo "⚠️  OpenCode ECC設定修正スクリプトまたはagentsディレクトリが見つかりません"
 fi
 
+# MarkItDown skill/command をOpenChamberから使えるように同期
+MARKITDOWN_SEED_DIR="/workspace/.devcontainer/opencode-seed"
+if [ -d "$MARKITDOWN_SEED_DIR" ]; then
+    mkdir -p \
+        /home/vscode/.opencode/skills/markitdown-converter/scripts \
+        /home/vscode/.opencode/commands \
+        /home/vscode/.opencode/instructions
+
+    install -m 755 \
+        "$MARKITDOWN_SEED_DIR/skills/markitdown-converter/scripts/convert.sh" \
+        /home/vscode/.opencode/skills/markitdown-converter/scripts/convert.sh
+    install -m 644 \
+        "$MARKITDOWN_SEED_DIR/skills/markitdown-converter/SKILL.md" \
+        /home/vscode/.opencode/skills/markitdown-converter/SKILL.md
+    install -m 644 \
+        "$MARKITDOWN_SEED_DIR/commands/to-markdown.md" \
+        /home/vscode/.opencode/commands/to-markdown.md
+    install -m 644 \
+        "$MARKITDOWN_SEED_DIR/instructions/markitdown-converter.md" \
+        /home/vscode/.opencode/instructions/markitdown-converter.md
+    echo "✅ MarkItDown skill/command を同期しました"
+fi
+
+if ! command -v uv >/dev/null 2>&1; then
+    echo "📦 uv をインストール中..."
+    if curl -LsSf https://astral.sh/uv/install.sh | sh >/tmp/uv-install.log 2>&1; then
+        export PATH="/home/vscode/.local/bin:$PATH"
+        echo "✅ uv インストール完了"
+    else
+        echo "⚠️  uv インストール失敗 (ログ: /tmp/uv-install.log)"
+    fi
+fi
+
+if command -v uv >/dev/null 2>&1 && ! command -v markitdown >/dev/null 2>&1; then
+    echo "📦 markitdown を uv でインストール中..."
+    if uv tool install markitdown >/tmp/markitdown-install.log 2>&1; then
+        echo "✅ markitdown インストール完了"
+    else
+        echo "⚠️  markitdown インストール失敗 (ログ: /tmp/markitdown-install.log)"
+    fi
+fi
+
+if [ -f /home/vscode/.opencode/opencode.json ]; then
+    python3 - <<'PY'
+import json
+from pathlib import Path
+
+path = Path("/home/vscode/.opencode/opencode.json")
+config = json.loads(path.read_text(encoding="utf-8"))
+instructions = config.get("instructions", [])
+entry = "instructions/markitdown-converter.md"
+if entry not in instructions:
+    instructions.append(entry)
+    config["instructions"] = instructions
+    path.write_text(json.dumps(config, indent=2, ensure_ascii=False) + "\n", encoding="utf-8")
+PY
+fi
+
 OPENCODE_LOG=/tmp/opencode-serve.log
 OPENCHAMBER_LOG=/tmp/openchamber.log