nspec

Specification-driven project management for AI-native development

nspec turns your backlog into structured markdown specs that AI coding assistants can read, execute, and update. It pairs every feature request (FR) with an implementation spec (IMPL), validates the entire graph, and exposes an MCP server so Claude Code (or any MCP-compatible agent) can autonomously pick up work, track tasks, run reviews, and advance specs through their lifecycle.

Install

pip install nspec

Also available via pipx, uv, and poetry. See the Getting Started guide.

Quick Start

nspec init              # Scaffold project (auto-detects your stack)
nspec mcp-config        # Generate MCP server config
nspec spec create --title "My feature" --priority P1
nspec validate          # Run 6-layer validation
nspec tui               # Interactive terminal UI

With the MCP server configured, Claude Code can autonomously work your backlog:

/ngo S001       — Start a work session on a spec
/nbacklog       — View the prioritized backlog
/nloop          — Autonomous mode: pick, execute, review, complete, repeat

At loop entry, /nloop seeds itself once with epic-wide FR intent via a loop-entry seed_context step (the epic_fr_context tool): it reads every member spec's Goal/Scope/Acceptance Criteria — regardless of state, so even un-started specs contribute — and grounds the whole run in what the epic intends, the FR-side complement to epic_context's per-spec delivered outcomes.

Features

• FR/IMPL Pairing — Every feature request gets a matching implementation spec with hierarchical tasks and acceptance criteria
• 6-Layer Validation — Format, pairing, dependencies, business logic, and ordering checks
• MCP Server — 89 tools over stdio, SSE, and HTTP transports for AI assistant integration
• Interactive TUI — Sortable table, detail panel, vim keybindings, search, follow mode, live reload, and in-terminal dependency-graph visualization (expand upstream/downstream, jump between linked specs)
• Dependency Graph — Circular reference detection, cross-epic ordering, priority inheritance
• Skills System — 29 slash commands for Claude Code (spec creation, review, triage, autonomous loops) plus Codex prompt templates
• Multi-Agent Queue — Parallel spec execution with git-worktree isolation, atomic claim/release, and lease-based recovery
• Checkout & Reservation — TTL-based spec leases prevent double-assignment across agents
• GitHub Issue Integration — Import issues as specs and sync status back to GitHub on completion
• Code Review — Automated review against spec criteria via configurable external agents (Codex, Gemini)
• Engineering Metrics — Velocity, quality, DORA metrics, and activity heatmap

Priority Model

• Epic priorities are global and unique. Epics rank against each other in one contiguous order (P1, P2, P3, …). Changing an epic's priority cascade-inserts it — the others shift up or down to keep every slot unique.
• Spec priorities (P0–P3) are scoped to their epic. A spec's priority only orders it against its siblings within the same epic — it is contained there and has no meaning across epics. Two specs may share a priority; ties break deterministically by spec ID. IDs are S/E + a zero-padded number (S001); the 3-digit space is a floor, not a cap — once it fills, IDs widen to four digits (S1000–S9999) automatically, and the allocator fails loud rather than ever reusing an ID. Changing a spec's priority bumps its epic siblings to make room (best-effort: because the P0–P3 range is smaller than the number of specs an epic can hold, siblings pile up at the floor priority once the range is exhausted rather than overflowing past it).
• Dependency order is the default sort, and it ignores P-numbers. The TUI's default sort:dependency orders specs by a topological sort of their deps, not by priority. A spec with no dependency edges to its siblings is an orphan and falls to the end of its epic, ordered only by its (often default) priority. To make the dependency graph authoritative, enable the optional gate [validation] enforce_epic_dependency_chain = true: validation then fails unless every epic's active specs form one connected dependency chain (branches are fine; disconnected islands and orphans are not). Wire specs together with add_dep to satisfy it.

Epic FR contract

Every epic carries a PRD-style contract so a reader can tell what it is for and when it is done without reverse-engineering it from child specs. create_spec(is_epic=True) scaffolds the FR from a dedicated epic template (src/nspec/resources/templates/epic/fr.md) with these sections: Goal, Why It Matters, Scope (In / Out), Definition of Complete, Child Specs, and Acceptance Criteria. Definition-of-Complete items are plain bullets describing the epic's end-state; only Acceptance Criteria are tracked checkboxes, so per-epic progress accounting is unchanged. A project can override the template by dropping its own copy at .novabuilt.dev/nspec/templates/epic/fr.md, which wins over the builtin.

Epic-level review

/nreview-epic <epic> batch-reviews every child spec of an epic. It reuses the single-spec review machinery rather than re-implementing it: for each child it runs the same chain /ngo and /nreview use — review_spec (mints the review prompt file) → execute_agent (dispatches to the external review agent, Codex/Gemini) → write_review_verdict (persists the verdict + a Review History row into the child's IMPL). So an epic review leaves the same durable per-spec audit trail a single-spec review does — not an ephemeral console table. It does not advance any spec's lifecycle status (it records verdicts only) and has no self-review path — the external agent always reviews, never the implementing agent. --converge wraps the per-spec chain in an iteration loop that surfaces cross-cutting themes (issues spanning 2+ specs) and drives atomic multi-file fixes until the epic's specs stop churning.

Running without reviews

Projects with no reviewable build artifact — an infrastructure repo whose changes are converged state rather than a diff — can turn reviews off honestly:

[review]
enabled = false
waive_reason = "infrastructure repo — no reviewable build artifact yet"

Completions then record a signed WAIVED — <reason> verdict instead of an approval, so the audit trail says plainly that review was waived and why. waive_reason is required: disabling reviews without one fails at config load. A waiver excuses the review, not the work — acceptance criteria and tasks must still be complete — and no agent can produce a WAIVED verdict, so it can't be used to rubber-stamp. Delete the two lines to re-enable.

Reviewer model & effort

Review runs on the top available model at moderate reasoning effort — [review.codex] defaults to gpt-5.6-sol at effort = "medium", [review.claude] to opus at high. The two knobs are not interchangeable: model tier bounds whether a finding is judged correctly, while effort buys depth of exploration within that ceiling. So effort is the dial to turn when review cost or latency matters — lower it rather than downgrading model. Cheap models remain the default for the non-judgement paths ([handoff], [docs]), where summarization is extraction rather than judgement.

Model ids retire without a CLI version bump and fail at call time, not config-load time, so a stale value looks like a reviewer hang rather than a config error — probe a new id before setting it. Rationale, role-by-role policy, and the verified legality matrix: docs/design/agent-model-selection.md.

Where review artifacts land

Everything nspec generates while working a spec lives under one root, work/specs/<spec-id>/, indexed by that spec's manifest.json:

work/specs/S314/
  manifest.json   prompts/   review/   output/   logs/

review/ holds the curated verdict and its JSON sidecar; output/ holds the raw agent transcript; prompts/ the review prompt; logs/ the per-agent execution logs. One directory therefore archives, hands off, or cleans up a spec's whole evidence trail. Spec-less agent output goes to work/logs/.

Upgrading: curated review artifacts used to be written to a second top-level root, work/agent-output/<id>/, which duplicated each round and left the curated copy out of the manifest. Nothing reads or writes that path now. Existing work/agent-output/ trees are left inert — gitignored scratch, never migrated, safe to delete by hand. There is no compatibility shim.

Documentation

Full documentation: novabuilt.dev/nspec

• Getting Started — Install, init, MCP setup
• CLI Reference — Full command docs
• Terminal UI — Interactive backlog browser & dependency visualization
• MCP Tools — Tool reference tables
• Skills Reference — Slash commands for Claude Code
• Configuration — Config file, env vars
• Contributing — Dev setup, testing

Development

poetry install
make test-quick    # Fast tests, fail-fast
make check         # Format + lint + typecheck

Type-aware verify: /ngo's verify step runs the command appropriate to what a spec changes — make test-quick for code, mkdocs build --strict for docs — instead of always running the full test suite. A spec selects its profile with a verify_profile: docs annotation in its FR (unannotated specs are code); projects add or override profiles under [verify.profiles] in config.toml, or per-run via an NSPEC_VERIFY_<PROFILE> env var (env > config > built-in default). Resolution fails closed: an unknown profile falls back to the code command, so verification is never silently skipped.

License

MIT License - see LICENSE for details.

Credits

Built with Poetry, Textual, Rich, and MCP.