ai-bender

Spec-driven scaffold for Claude Code. bender is a Go CLI that installs a .claude/ workspace into your projects and gives you slash commands you run inside Claude Code: /cry, /plan, /tdd, /ghu, /implement.

The binary never calls an LLM. It scaffolds, validates, and inspects. Claude Code is the executor.

Install

Homebrew (macOS / Linux):

brew install mayckol/tap/bender

curl | sh (macOS / Linux, no Go required):

curl -fsSL https://raw.githubusercontent.com/mayckol/ai-bender/main/scripts/install.sh | sh

Env overrides: BENDER_VERSION=v0.23.0, BENDER_PREFIX=$HOME/.local (avoids sudo).

go install:

go install github.com/mayckol/ai-bender/cmd/bender@latest

From source:

git clone https://github.com/mayckol/ai-bender
cd ai-bender
make build install

Ensure the install dir (/usr/local/bin, $(go env GOPATH)/bin, or $BENDER_PREFIX/bin) is on your PATH. Verify with bender version.

Quickstart

cd ~/projects/my-service
bender init                 # scaffolds .claude/ and .bender/
bender server               # live viewer on http://localhost:4317
# open the project in Claude Code:
#   /cry "users need roles"   → /cry confirm
#   /plan                     → /plan confirm
#   /tdd (optional)           → /tdd confirm
#   /ghu
bender sessions list        # inspect on-disk sessions

Pipeline stages

Each stage reads its inputs from .bender/artifacts/, writes its outputs there, and emits events to .bender/sessions/<id>/events.jsonl.

Stage	Command	Inputs	Outputs
bootstrap	/bender-bootstrap	discovered project files	.bender/artifacts/constitution.md
cry	/cry <request>	user request	.bender/artifacts/cry/<slug>-<ts>.md
plan	/plan	approved cry	spec + data model + risks + tasks under .bender/artifacts/{specs,plan}/
tdd (optional)	/tdd	approved plan	prose test scaffolds under .bender/artifacts/plan/tests/
ghu	/ghu	approved spec + tasks	code + .bender/artifacts/ghu/run-<ts>-report.md
implement	/implement <task>	same as /ghu, scoped	same report path
doctor	/bender-doctor	.claude/ catalog	stdout health report

Every draft artifact carries status: draft until you run /<stage> confirm. /plan is design-only — it refuses implementation requests while the plan is in awaiting_confirm. /ghu refuses to start if the plan set is still draft.

Worktree isolation

Every /ghu and /implement session runs inside its own git worktree on bender/session/<id>. Your main working tree is never touched. Two sessions can run in parallel against the same repo without colliding.

Layout:

<repo>/.bender/worktrees/<session-id>/   # session worktree (gitignored)
<repo>/.bender/sessions/<session-id>/    # state.json + events.jsonl

Override the worktree root in .bender/config.yaml:

worktree:
  root: ../bender-worktrees

bender worktree {create,list,remove,prune} manages them. When git is missing, the repo is bare, or the repo is mid-rebase/merge, bender refuses with a specific exit code — it never falls back to writing in the main tree.

Workflow linkage

Consecutive sessions on the same feature branch (e.g. /tdd → /ghu) share a workflow_id, so the live viewer stitches them into one timeline. bender workflow resolve --key <branch> returns the id; bender worktree create --workflow-id ... --workflow-parent ... persists it.

Binary commands

Global flags: --project, --config, --no-color, --quiet, --verbose.

Command	Purpose
bender init	Scaffold .claude/ + .bender/ from embedded defaults. Idempotent.
bender sync-defaults [--force]	Materialise embedded defaults added since init.
bender register-project <path> [--name]	Add a project to ~/.bender/workspace.yaml.
bender list-projects	List registered projects; marks current, available, missing.
bender doctor	Validate the catalog.
bender sessions list	List on-disk sessions.
bender sessions show <id>	NDJSON dump of events.jsonl. Pipe to jq.
bender sessions export <id>	Single JSON doc (state + events) matching the viewer ingest contract.
bender sessions validate <id>	Check state.json + events.jsonl against the v1 schema.
bender sessions clear [<id>] [--all]	Remove session data. Artifacts under .bender/artifacts/ are preserved.
bender sessions pr <id>	Opt-in: push the session branch and open a PR via gh / glab.
bender worktree create <id>	Create a session worktree. Skills call this automatically.
bender worktree list	Show every session's worktree status.
bender worktree remove <id>	Tear down one worktree; keep the session branch.
bender worktree prune	Bulk-clean completed/aborted worktrees.
bender workflow resolve --key <branch>	Return the workflow id a new session should inherit.
bender event emit --session --type --actor-kind --actor-name --payload	Atomic append of one event line to events.jsonl. Skills call this; humans rarely.
bender server [--port] [--foreground]	Start the live viewer.
bender update [--check]	Replace the binary with the latest release.
bender version	Print binary version.

Every binary verb has Bash + PowerShell fallbacks under .specify/scripts/{bash,powershell}/ and extension scripts under .specify/extensions/*/scripts/. Install the binary globally for the full surface; the fallbacks cover machines without Go installed.

Slash commands (run in Claude Code)

Materialised by bender init under .claude/skills/<name>/SKILL.md.

• /cry [--type=<bug|feature|performance|architectural>] <request> — capture intent. /cry confirm approves.
• /plan [--from=<cry-artifact>] — produce spec + data model + risks + tasks under one timestamp. /plan confirm flips the set to approved. Design-only: never writes code. Follow-ups during awaiting_confirm re-plan the artifacts; implementation-shaped messages are refused.
• /tdd — mirror the source tree under .bender/artifacts/plan/tests/ with prose scaffolds. /tdd confirm approves.
• /ghu [--inline | --bg] [--only=<task>] [--skip=<name>[,...]] [--abort-on-failure] — execute the approved plan. First action provisions a worktree. Only stage that writes code. When /tdd scaffolds exist, runs in TDD mode (Red → Green → Refactor). Otherwise walks scout → architect → crafter ∥ tester → linter → reviewer ∥ sentinel ∥ benchmarker ∥ scribe → report.
• /implement <task> — /ghu scoped to one task.
• /bender-doctor — narrative wrapper around bender doctor.
• /bender-bootstrap — fill pending constitution sections from README + manifests.

--skip accepts linter/lint, tester/test, reviewer/review, sentinel/security, benchmarker/perf, scribe/docs, surgeon/refactor, architect, review-sweep. crafter and scout are not skippable.

/ghu defaults to --inline: the workflow runs in the current conversation so the main chat streams live progress while bender server's web UI tails the same events.jsonl in parallel. Pass --bg to run inside an isolated subagent via Claude Code's Agent tool (run_in_background: true) — main chat stays silent until completion; use this when you want the main conversation free for other work.

Agents

Agent	Purpose	Write scope
crafter	Implement production code with minimum-diff edits	source files
tester	Author + run tests; enumerate edge cases	tests / fixtures only
reviewer	Critique against spec / constitution	read-only; findings only
linter	Run linters/formatters; safe autofixes	autofix-only
architect	Design + boundary validation	writes during /plan; read-only during /ghu
scribe	Keep docs in sync with code	docs/comments only
scout	Read-only codebase exploration with caching	zero
sentinel	Security analysis (secrets, deps, inputs, auth, crypto)	read-only; findings only
benchmarker	Performance analysis with measurement	read-only; findings only
surgeon	Behavior-preserving refactors (tests green before and after)	source files

Observability

Every stage emits structured events via bender event emit (atomic O_APPEND | O_SYNC writes). Two progress levels during /ghu and /implement:

• Session-level — orchestrator_progress events carry {percent, current_step, completed_nodes, total_nodes}. percent = round(100 × completed / total) over the DAG walk.
• Agent-level — agent_progress events carry {agent, percent, current_step}, one tick per internal sub-step so the bar advances smoothly.

Real-time viewer

bender server                 # detaches, pid + log under .bender/
bender server --port 4000
bender server --foreground
bender server status
bender server stop

Open http://localhost:4317/:

• / — session list with live updates.
• /sessions/<id> — live timeline: per-agent rows, findings panel, file-changed summary, report link. Freezes on session_completed.

When /ghu --bg dispatches, the skill prints the viewer URL and best-effort-opens your browser. Sessions that share a workflow_id merge onto one timeline. Every event's raw JSON has a copy-to-clipboard button.

Init preferences

bender init asks one confirm: Open a pull request on successful /ghu runs? The answer persists to .bender/selection.yaml under preferences.open_pr_on_success. When enabled, the after_implement pr extension runs bender session pr <id> after a successful run. Adapter failures never fail the implement run.

Project layout after bender init

your-project/
├── .claude/                        # Claude Code–native artefacts
│   ├── agents/                     #   default subagents
│   └── skills/                     #   slash-command + worker skills
└── .bender/                        # bender-owned config + runtime
    ├── pipeline.yaml               #   declarative execution DAG
    ├── groups.yaml                 #   named skill-selector bundles
    ├── config.yaml                 #   per-project overrides
    ├── selection.yaml              #   init-time selection + preferences
    ├── artifacts/                  #   pipeline outputs (commit this)
    │   ├── constitution.md
    │   ├── cry/<slug>-<ts>.md
    │   ├── specs/<slug>-<ts>.md
    │   ├── plan/{data-model,api-contract,risk-assessment,tasks}-<ts>.md
    │   └── ghu/run-<ts>-report.md + {reviews,security,perf}/
    ├── worktrees/<session-id>/     #   per-session git worktree (gitignored)
    ├── sessions/<id>/              #   state.json + events.jsonl (gitignored)
    └── cache/                      #   scout caches (gitignored)

Customising

Claude Code reads .claude/agents/*.md and .claude/skills/*/SKILL.md directly — no registration step.

Change an agent's skill binding — edit .claude/agents/<name>.md. bender doctor validates the result.

Add an agent — drop .claude/agents/<your-name>.md with standard frontmatter.

Add a skill — drop .claude/skills/<name>/SKILL.md; every matching agent selector picks it up.

Per-project overrides — .bender/config.yaml:

agents:
  crafter:
    skills:
      add: [project-specific-migration-check]
      remove: [check-data-model]
    write_scope:
      deny_add: ["internal/legacy/**"]

Reshape the /ghu DAG — edit .bender/pipeline.yaml (nodes, dependencies, max_concurrent, when expressions). bender doctor validates edits.

Multi-project workspace

bender register-project <path> adds a project to ~/.bender/workspace.yaml (honors $XDG_CONFIG_HOME). bender list-projects shows them. Every binary command accepts --project=<name>.

Documentation

• Constitution: .specify/memory/constitution.md
• Feature specs: specs/<NNN>-<slug>/
• Viewer HTTP API: ui/README.md

License

MIT. See LICENSE.