feat: add Devin (Cognition AI) as a gstack host (Phase 1 + Phase 2)

.gitignore

@@ -18,6 +18,8 @@ bin/gstack-global-discover
 .openclaw/
 .hermes/
 .gbrain/
+.cognition/
+.devin/
 .context/
 extension/.auth.json
 # xterm assets are vendored from npm at build time; not source-of-truth.

AGENTS.md

@@ -103,6 +103,31 @@ bun run skill:check      # health dashboard for all skills
   helper resolves state roots through `CLAUDE_PLUGIN_DATA` / `GSTACK_HOME` so plugin
   installs work on every platform.
 
+## Multi-agent support
+
+gstack works with multiple AI coding agents via typed host configs in `hosts/`.
+Each agent gets its own generated SKILL.md output:
+
+| Host | Generate | Skill location |
+| --- | --- | --- |
+| Claude Code (default) | `bun run gen:skill-docs --host claude` | `<skill>/SKILL.md` (in-tree) |
+| OpenAI Codex CLI | `bun run gen:skill-docs --host codex` | `.agents/skills/gstack-*/` |
+| Factory Droid | `bun run gen:skill-docs --host factory` | `.factory/skills/gstack-*/` |
+| OpenCode | `bun run gen:skill-docs --host opencode` | `.opencode/skills/gstack-*/` |
+| Cursor | `bun run gen:skill-docs --host cursor` | `.cursor/skills/gstack-*/` |
+| **Devin (Cognition AI)** | `bun run gen:skill-docs --host devin` | `.devin/skills/gstack-*/` |
+
+For Devin specifically, see [`docs/DEVIN.md`](docs/DEVIN.md). Two surfaces share
+the same skills:
+
+- **Devin for Terminal CLI** (local) reads from `.devin/skills/` (project) and
+  `~/.config/devin/skills/` (global). Run `./setup --host devin` for global
+  install on your machine, or `./setup --host devin --local` from inside any
+  project repo to commit per-repo.
+- **Devin remote/cloud sessions** clone the repo into a fresh Ubuntu VM and also
+  discover skills under `.devin/skills/`. The canonical commit-to-repo install is
+  `./setup --host devin --local` from inside your project repo.
+
 ## Key conventions
 
 - SKILL.md files are **generated** from `.tmpl` templates. Edit the template, not the output.

devin-setup/SKILL.md.tmpl

@@ -0,0 +1,234 @@
+---
+name: devin-setup
+preamble-tier: 1
+version: 1.0.0
+description: |
+  Devin-only one-shot setup. Registers /ship and /land-and-deploy as Devin
+  Playbooks for this user/org, creates an initial Knowledge Note linking the
+  project's ETHOS.md and AGENTS.md, and verifies that `devin_mcp` is reachable
+  for sub-session orchestration. Run this once per Devin workspace after
+  cloning a gstack-equipped repo.
+  Use when: "devin setup", "register playbooks", "set up gstack for devin",
+  "wire devin_mcp", "set up knowledge notes for this repo".
+triggers:
+  - devin setup
+  - register playbooks
+  - setup knowledge notes
+allowed-tools:
+  - Bash
+  - Read
+  - Grep
+  - Glob
+---
+
+{{PREAMBLE}}
+
+# /devin-setup — Wire gstack into this Devin workspace
+
+You are helping the user wire gstack into their Devin workspace. This is the
+**Devin-equivalent of `/setup-gbrain`**: it ensures the cross-session memory
+(Knowledge Notes) and orchestration (Playbooks, sub-sessions) are ready before
+the user runs `/ship`, `/land-and-deploy`, `/review`, or any of the
+review-army-style skills.
+
+This skill is idempotent — running it again is safe and only adds missing
+pieces.
+
+## When to invoke
+
+Run this once per Devin workspace, ideally right after `./setup --host devin --local`
+generates the `.devin/skills/` tree. Repeat anytime gstack changes how it
+uses Devin's MCP surface.
+
+## Instructions
+
+### Step 1: Verify devin_mcp is reachable
+
+The whole skill assumes the agent has access to the `devin_mcp` tool with
+`devin_session_create`, `devin_knowledge_manage`, and `devin_playbook_manage`.
+
+Try a no-op call:
+
+```
+tool_name = "devin_knowledge_manage"
+tool_args = {
+  "action": "list",
+  "first": 1
+}
+```
+
+If this returns an authorization / "tool unavailable" error, stop and tell the
+user: "devin_mcp is not enabled for this Devin account. Phase 2 features
+(sub-session second opinions, Knowledge Notes memory, Playbook registration)
+require `devin_mcp` access. Continuing without these — gstack still works,
+but cross-session memory and outside-voice reviews will be no-ops."
+
+If the call succeeds, continue.
+
+### Step 2: Derive the repo identifier
+
+```bash
+REPO_URL=$(git config --get remote.origin.url)
+REPO_SLUG=$(echo "$REPO_URL" | sed -E 's#(git@github\.com:|https?://github\.com/)##; s#\.git$##')
+echo "REPO_SLUG: $REPO_SLUG"
+```
+
+Remember `$REPO_SLUG` — every Knowledge Note created by this skill will be
+pinned to it.
+
+### Step 3: Register /ship as a Devin Playbook
+
+Read the generated /ship skill markdown:
+
+```bash
+SHIP_SKILL=".devin/skills/gstack-ship/SKILL.md"
+[ -f "$SHIP_SKILL" ] || SHIP_SKILL=".agents/skills/gstack-ship/SKILL.md"
+[ -f "$SHIP_SKILL" ] || SHIP_SKILL=".github/skills/gstack-ship/SKILL.md"
+[ -f "$SHIP_SKILL" ] || SHIP_SKILL=".cognition/skills/gstack-ship/SKILL.md"  # legacy
+cat "$SHIP_SKILL" | head -1
+```
+
+If found, register as a Playbook:
+
+```
+tool_name = "devin_playbook_manage"
+tool_args = {
+  "action": "create",
+  "title": "gstack: /ship",
+  "body": "<full markdown content of $SHIP_SKILL>",
+  "macro": "!ship"
+}
+```
+
+Before creating, list existing playbooks via
+`{"action": "list", "first": 100}` and check whether one titled exactly
+`gstack: /ship` already exists. If it does, prefer
+`{"action": "update", "playbook_id": "<existing>"}` over creating a duplicate
+(v3 PUT is full-replace — pass the full body).
+
+### Step 4: Register /land-and-deploy as a Devin Playbook
+
+Same procedure as Step 3, but for `/land-and-deploy`:
+
+```bash
+LAND_SKILL=".devin/skills/gstack-land-and-deploy/SKILL.md"
+[ -f "$LAND_SKILL" ] || LAND_SKILL=".agents/skills/gstack-land-and-deploy/SKILL.md"
+[ -f "$LAND_SKILL" ] || LAND_SKILL=".github/skills/gstack-land-and-deploy/SKILL.md"
+[ -f "$LAND_SKILL" ] || LAND_SKILL=".cognition/skills/gstack-land-and-deploy/SKILL.md"  # legacy
+```
+
+Register with:
+
+```
+tool_name = "devin_playbook_manage"
+tool_args = {
+  "action": "create",
+  "title": "gstack: /land-and-deploy",
+  "body": "<full markdown content of $LAND_SKILL>",
+  "macro": "!land_and_deploy"
+}
+```
+
+Same dedup-check (list → update if exists) as Step 3.
+
+### Step 5: Seed the project's Knowledge Notes
+
+Create the first project-pinned Knowledge Note describing this repo's gstack
+ETHOS, so future sessions get context on the project's design philosophy when
+they start a new skill that calls Knowledge Notes load.
+
+Read the local ETHOS file:
+
+```bash
+ETHOS_FILE="ETHOS.md"
+[ -f "$ETHOS_FILE" ] || ETHOS_FILE=".devin/skills/gstack/ETHOS.md"
+[ -f "$ETHOS_FILE" ] || ETHOS_FILE=".cognition/skills/gstack/ETHOS.md"  # legacy
+[ -f "$ETHOS_FILE" ] && head -200 "$ETHOS_FILE"
+```
+
+If ETHOS.md exists, register it as a Knowledge Note:
+
+```
+tool_name = "devin_knowledge_manage"
+tool_args = {
+  "action": "create",
+  "name": "gstack: ETHOS for <REPO_SLUG>",
+  "body": "<full ETHOS.md content (truncate to first 30KB if larger)>\n\n---\nPinned by /devin-setup. This note describes the design philosophy that should guide all gstack skill outputs in this repo.",
+  "trigger": "When starting a new gstack skill in this repo, especially /office-hours, /plan-ceo-review, /investigate, or /retro.",
+  "pinned_repo": "<REPO_SLUG>"
+}
+```
+
+Dedup check: list with `{"action": "list", "search": "ETHOS for <REPO_SLUG>", "pinned_repo": "<REPO_SLUG>"}`
+and update if it exists.
+
+If `AGENTS.md` exists in the repo, register it as a second Knowledge Note:
+
+```
+tool_name = "devin_knowledge_manage"
+tool_args = {
+  "action": "create",
+  "name": "gstack: AGENTS.md for <REPO_SLUG>",
+  "body": "<full AGENTS.md content>",
+  "trigger": "When starting any gstack skill in this repo, to load the slash-command catalog and platform conventions.",
+  "pinned_repo": "<REPO_SLUG>"
+}
+```
+
+### Step 6: Print a summary
+
+Output exactly this block (filling in the values you observed):
+
+```
+gstack ↔ Devin wiring complete
+
+Repo: <REPO_SLUG>
+Playbooks registered:
+  - gstack: /ship           (macro !ship,           id: <playbook_id_1>)
+  - gstack: /land-and-deploy (macro !land_and_deploy, id: <playbook_id_2>)
+Knowledge Notes seeded:
+  - gstack: ETHOS for <REPO_SLUG>      (id: <note_id_1>)
+  - gstack: AGENTS.md for <REPO_SLUG>  (id: <note_id_2>)
+Sub-session orchestration:
+  - devin_session_create: REACHABLE
+  - devin_knowledge_manage: REACHABLE
+  - devin_playbook_manage: REACHABLE
+
+Next steps:
+  - Run /ship (or type !ship) to land your next change.
+  - Run /review on any branch — it will spawn parallel review-army sub-sessions.
+  - Run /office-hours for product brainstorming with cross-session memory.
+```
+
+If any step failed, replace the corresponding line with `FAILED: <one-line reason>`
+and continue with the rest. Setup is best-effort — partial wiring is fine.
+
+### Step 7: (optional) Set up a recurring health check
+
+Ask:
+
+> Want a weekly Devin schedule that runs `/health` on this repo every Monday at 09:00?
+> A) Yes, schedule weekly /health
+> B) No thanks
+
+If A, register the schedule via `devin_mcp`:
+
+```
+tool_name = "devin_schedule_manage"
+tool_args = {
+  "action": "create",
+  "name": "gstack weekly /health for <REPO_SLUG>",
+  "prompt": "Run /health on this repo and post the result.",
+  "frequency": "0 9 * * 1",
+  "schedule_type": "recurring",
+  "notify_on": "failure",
+  "agent": "devin"
+}
+```
+
+If the schedule manager is unavailable, note and continue.
+
+## Done
+
+Setup complete. All future gstack skills in this repo will use Knowledge Notes
+for memory and sub-sessions for second-opinion reviews automatically.