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-----+---------+--------------+--------+---------+-----
     IDEA      SHAPE          SPEC     PLAN      BUILD

Ridgeline

Build harness for long-horizon software execution using AI agents.

Ridgeline decomposes large software ideas into phased builds using a multi-agent pipeline (shaper, specifier, planner, builder, reviewer) driven by the Claude CLI. It manages state through git checkpoints, tracks costs, and supports resumable execution when things go wrong.

How it works

1. Shape -- describe what you want built. The shaper agent analyzes your codebase and asks clarifying questions to produce a structured shape document.
2. Specify -- an ensemble of three specialist agents (completeness, clarity, pragmatism) drafts spec proposals, then a synthesizer merges them into spec.md, constraints.md, and optionally taste.md.
3. Plan -- an ensemble of three specialist planners (simplicity, thoroughness, velocity) proposes phase decompositions, then a synthesizer merges them into numbered phase files with acceptance criteria.
4. Build -- for each phase the builder agent implements the spec inside your repo, then creates a git checkpoint.
5. Review -- the reviewer agent (read-only) checks the output against the acceptance criteria and returns a structured verdict. On failure, the harness generates a feedback file from the verdict for the builder's next attempt.
6. Retry or advance -- failed phases are retried up to a configurable limit; passing phases hand off context to the next one.

Install

npm install -g ridgeline

Ridgeline requires the Claude CLI to be installed and authenticated.

For sandboxing (recommended), install one of:

• macOS/Linux: Greywall -- brew install greywall (domain-level network allowlisting + filesystem isolation)
• Linux: bubblewrap -- apt install bubblewrap (full network block + read-only filesystem)

Sandboxing is on by default when a provider is detected. No flags needed.

Quick start

# Auto-advance through the pipeline (shape → spec → plan → build)
ridgeline my-feature "Build a REST API for task management"

# Or run each stage individually
ridgeline shape my-feature "Build a REST API for task management"
ridgeline spec my-feature
ridgeline plan my-feature
ridgeline dry-run my-feature   # preview before committing
ridgeline build my-feature

# Resume after a failure (re-run build)
ridgeline build my-feature

# Rewind to an earlier stage and redo from there
ridgeline rewind my-feature --to spec

# Clean up stale worktrees from failed builds
ridgeline clean

Commands

ridgeline [build-name] [input] (default)

Auto-advances the build through the next incomplete pipeline stage (shape → spec → plan → build). Accepts all flags from the individual commands.

ridgeline shape [build-name] [input]

Gathers project context through interactive Q&A and codebase analysis. Produces shape.md in the build directory. Accepts an optional input argument -- a file path to an existing document or a natural language description.

| Flag | Default | Description | |------|---------|-------------| | --model <name> | opus | Model for shaper agent | | --timeout <minutes> | 10 | Max duration per turn |

ridgeline spec [build-name]

Runs the specifier ensemble: three specialist agents (completeness, clarity, pragmatism) draft proposals in parallel, then a synthesizer merges them into spec.md, constraints.md, and optionally taste.md.

| Flag | Default | Description | |------|---------|-------------| | --model <name> | opus | Model for specifier agents | | --timeout <minutes> | 10 | Max duration per turn | | --max-budget-usd <n> | none | Halt if cumulative cost exceeds this |

ridgeline plan [build-name]

Runs the planner ensemble: three specialist planners (simplicity, thoroughness, velocity) propose phase decompositions in parallel, then a synthesizer merges them into numbered phase files (01-slug.md, 02-slug.md, ...) stored in the build's phases/ directory.

| Flag | Default | Description | |------|---------|-------------| | --model <name> | opus | Model for planner agents | | --timeout <minutes> | 120 | Max planning duration | | --constraints <path> | auto | Path to constraints file | | --taste <path> | auto | Path to taste file |

ridgeline dry-run [build-name]

Displays the execution plan without invoking builders or reviewers. Accepts the same flags as plan.

ridgeline build [build-name]

Executes the full build pipeline: build each phase, evaluate, retry on failure, and advance on success.

| Flag | Default | Description | |------|---------|-------------| | --model <name> | opus | Model for builder and reviewer | | --timeout <minutes> | 120 | Max duration per phase | | --check-timeout <seconds> | 1200 | Max duration for check command | | --max-retries <n> | 2 | Max reviewer retry loops per phase | | --check <command> | from constraints | Baseline check command | | --max-budget-usd <n> | none | Halt if cumulative cost exceeds this | | --constraints <path> | auto | Path to constraints file | | --taste <path> | auto | Path to taste file | | --context <text> | none | Extra context appended to builder and planner prompts | | --unsafe | off | Disable sandbox auto-detection |

The build command automatically resumes from the last successful phase if previous state exists. Each build runs in an isolated git worktree -- completed phases are reflected back to your branch, and failed builds leave the worktree intact for inspection.

ridgeline rewind <build-name>

Resets pipeline state to a given stage and deletes downstream artifacts.

| Flag | Default | Description | |------|---------|-------------| | --to <stage> | (required) | Stage to rewind to: shape, spec, or plan |

ridgeline clean

Removes all build worktrees under .ridgeline/worktrees/ and their associated WIP branches. Use this after inspecting a failed build.

Build directory structure

.ridgeline/
├── settings.json      # Optional project-level config (network allowlist, etc.)
├── worktrees/         # Git worktrees for active builds
│   └── <build-name>/  # Isolated working directory per build
└── builds/<build-name>/
    ├── shape.md           # Structured project context (from shaper)
    ├── spec.md            # What to build
    ├── constraints.md     # Technical constraints and check commands
    ├── taste.md           # Optional coding style preferences
    ├── phases/
    │   ├── 01-scaffold.md
    │   ├── 01-scaffold.feedback.md  # Generated by harness on review failure
    │   ├── 02-core.md
    │   └── ...
    ├── state.json         # Phase statuses, retries, timestamps, git tags
    ├── budget.json        # Per-invocation cost tracking
    ├── trajectory.jsonl   # Event log (plan/build/eval start/complete)
    └── handoff.md         # Context passed to the next phase

Configuration resolution

Constraint and taste files are resolved in order:

1. CLI flag (--constraints <path>)
2. Build-level (.ridgeline/builds/<build-name>/constraints.md)
3. Project-level (.ridgeline/constraints.md)

Project-level settings (network allowlist, etc.) are loaded from .ridgeline/settings.json. See SECURITY.md for details.

Development

npm install
npm run build        # Compile TypeScript and copy agent prompts
npm run dev          # Watch mode
npm test             # Typecheck, lint, and run unit tests
npm run test:unit    # Unit tests only (vitest)
npm run test:e2e     # End-to-end tests
npm run test:watch   # Watch mode
npm run lint         # Run all linters (oxlint, markdownlint, agnix, fallow)
npm run typecheck    # Type-check without emitting

License

MIT