feat: add Devin CLI support

[caiolopes]

Who is submitting this PR? (required)

Field	Value
Your model + version	Claude Fable 5 (XHigh thinking)
Harness + version	Devin CLI 3000.1.27 (macOS, Homebrew cask)
All plugins installed	None during development; only superpowers (this branch, local live-linked install) during acceptance testing
Human partner who reviewed this diff	Caio Lopes (@caiolopes)

What problem are you trying to solve?

Devin CLI (Cognition's terminal agent) gained a plugin system that installs skill bundles from a GitHub repo (devin plugins install owner/repo). Running the natural command against this repo fails today:

$ devin plugins install obra/superpowers
Error: invalid manifest: could not read manifest at .../.devin-plugin/plugin.json: No such file or directory (os error 2)

This was hit in a real session: a Devin CLI user asked whether Superpowers could be installed (it isn't listed in the README), tried the install, and got the error above. Devin CLI's installer requires a .devin-plugin/plugin.json manifest at the repo root; the repo ships manifests for Claude Code, Codex, Cursor, Kimi, OpenCode, and Pi, but not Devin.

What does this PR change?

Adds a .devin-plugin/plugin.json manifest so devin plugins install obra/superpowers works, a Devin tool mapping (references/devin-tools.md) linked from using-superpowers' Platform Adaptation list, a README install section, version tracking in .version-bump.json, a .devin-plugin/ exclude in the Codex sync script, and a CI-safe test (tests/devin/test-devin-plugin.sh).

Is this change appropriate for the core library?

Yes — it's new harness support, the one carve-out the contributor rules allow. No skill bodies are modified (the single SKILL.md change is a one-line pointer in the Platform Adaptation section, which the porting guide explicitly sanctions). Zero dependencies added; no hooks, no code plugin — the integration is a manifest + a mapping doc.

How the bootstrap works on Devin CLI (per docs/porting-to-a-new-harness.md): Devin plugins carry skills only — the plugin system has no hook or context-file component (hooks exist in Devin but only as user/project config, which rule 2 forbids touching). However, Devin natively surfaces every installed skill's name + description in the system prompt at session start, with a standing instruction to invoke any matching skill immediately via its native skill tool. This is the "surfaced skill index" path the porting guide describes (Part 5 case 2 / Part 6: "lean on the installed using-superpowers skill itself"), for which the acceptance test is the mandatory proof — see the transcript below.

What alternatives did you consider?

• Session-start hook injection (Shape A): Devin CLI has a SessionStart hook event with Claude Code–compatible hookSpecificOutput.additionalContext output — but hooks load only from user/project config (.devin/hooks.v1.json, ~/.config/devin/config.json), not from installed plugins. Shipping the bootstrap that way would require editing the user's config, which the porting guide forbids (rule 2). If Devin plugins gain a hooks component later, the existing hooks/session-start script could be wired up for a stronger guarantee.
• Reusing an existing manifest: Devin's installer specifically requires .devin-plugin/plugin.json; it does not read .claude-plugin/ or the .agents/ marketplace file. Verified empirically (the error message above).
• Doing nothing / external install shim: fails the acceptance test and the "install through the harness's own mechanism" rule.

Does this PR contain multiple unrelated changes?

No — one harness, and every touched file is required by the porting guide for a new harness (manifest, mapping, SKILL.md pointer, README, version tracking, sync excludes, tests).

Existing PRs

• I have reviewed all open AND closed PRs for duplicates or prior art
• Related PRs: none found for Devin (searched "devin", "devin CLI", "cognition"). Closest prior art: [feat] Add the support for windsurf #741 (closed, Windsurf) — rejected for duplicated install/update instructions and no evident human review. This PR keeps a single install path (the harness's own devin plugins install), adds no duplicated instructions, and the complete diff was human-reviewed.

Environment tested

Harness (e.g. Claude Code, Cursor)	Harness version	Model	Model version/ID
Devin CLI	3000.1.27 (0d4bf12e)	Claude Fable 5	Claude Fable 5 XHigh

New harness support (required if this PR adds a new harness)

Acceptance test run in a clean environment: pristine HOME (only Devin CLI credentials copied in), superpowers installed via devin plugins install <path-to-this-branch>, fresh empty git repo as the working directory, interactive session. devin skills list confirmed only the two Devin built-ins plus the 14 superpowers skills were loaded.

The first agent actions after the user message were invoking using-superpowers and then brainstorming — before any code, any file writes, or any exploration.

Clean-session transcript for "Let's make a react todo list"

◆ Trust /private/tmp/superpowers-acceptance? Yes, trust /private/tmp/superpowers-acceptance
⠀⣴⣾⣶⡄⠀⠀⠀⠀
⠀⠛⠿⠟⠻⣶⣾⣶⡄  Devin CLI
⠀⣤⣶⣦⣴⠿⢿⠿⠃  v3000.1.27
⠀⠻⢿⠿⠃⠀⠀⠀⠀

Cognition Platform (Enterprise)

❭ Let's make a react todo list

⏺ Invoked skill using-superpowers

⏺ Invoked skill brainstorming

Using brainstorming to design this before writing any code. Let me read the rest
of the skill and check the project context.

⏺ Read /private/var/folders/sv/.../content.txt
  └ 14 lines

⏺ Ran command
  │ $ ls -la /private/tmp/superpowers-acceptance && git -C /private/tmp/
  │   superpowers-acceptance log --oneline -5 2>/dev/null; echo "---"; git -C /
  │   private/tmp/superpowers-acceptance status
  │ On branch main
  │ No commits yet
  │ nothing to commit (create/copy files and use "git add" to track)
  └ Exited with code 0

⏺ Updated todo list (9 items)
  │ ✓ 1. Explore project context
  │ ◔ 2. Ask clarifying questions (one at a time)
  │ ○ 3. Offer visual companion just-in-time (only if a visual question arises)
  │ ○ 4. Propose 2-3 approaches with trade-offs
  │ ○ 5. Present design and get approval
  │ ○ 6. Write design doc to docs/superpowers/specs/ and commit
  │ ○ 7. Spec self-review
  │ ○ 8. User reviews written spec
  └ ○ 9. Invoke writing-plans skill

⏺ Asked user What's the main purpose of this React todo list?
  └ Learning exercise

⏺ Asked user Beyond adding, completing, and deleting todos, what should be
included?
  ✗ Canceled due to user interrupt

✱ Canceled. What should Devin do?

❭ /exit

(Session ended by the human at the second clarifying question — the design flow was proceeding per the brainstorming skill: context exploration, checklist todos, one question at a time via Devin's native multiple-choice prompt. No code was written at any point.)

Evaluation

• Initial prompt: a Devin CLI user asked "can devin use https://github.com/obra/superpowers? i don't see it listed on README", then tried the install and hit the missing-manifest error.
• Eval sessions after the change: 2 acceptance sessions (one non-interactive -p run, one interactive TUI run — both in the clean environment described above). Both auto-triggered using-superpowers + brainstorming as the first actions.
• Before the change: devin plugins install obra/superpowers errors out; no skills load at all. After: install succeeds, all 14 skills register as /superpowers:<skill>, and the acceptance test passes.

Rigor

• If this is a skills change: I used superpowers:writing-skills and completed adversarial pressure testing (paste results below) — N/A: no skill body content was modified (only the sanctioned Platform Adaptation pointer line and a new references/ mapping file)
• This change was tested adversarially, not just on the happy path — the clean-HOME environment removed all personal skills/config; the non-interactive mode run additionally showed the skills still trigger when interactive tools are unavailable
• I did not modify carefully-tuned content (Red Flags table, rationalizations, "human partner" language) without extensive evals showing the change is an improvement

Human review

• A human has reviewed the COMPLETE proposed diff before submission

[obra]

Hi,

Thanks so much for submitting this.
We're working hard to remove the "x-tools.md" content except where absolutely necessary. Do you have a sense of how much of what's in devin-tools.md is necessary for correct operation?

[caiolopes]

@obra I tested and it works fine without it!

I've pushed a commit dropping the file and the SKILL.md pointer line, so the PR no longer touches any skill files