Policy-as-code for AI coding agents: route each changed file to its proof commands, then enforce them through CLI, MCP, git hooks and CI.
AI proposes a change. The file's own toolchain proves it. The build refuses what skipped a check.

Measured: the commands that prove a change, build-enforced (evidence). Agents: llms.txt; chats: CHAT.md.

Start: install/use · agents · chat · adapters

What it does

Thea turns repository policy into executable verification. atlas.yaml tells agents what proves each file's change; CLI, MCP, hooks, CI and adapters enforce it. Gates report PASS, FAIL or NOT RUN — missing tools never become green.

---
config:
  theme: base
  themeVariables:
    primaryColor: "#e6f2e7"
    primaryBorderColor: "#6f9f73"
    primaryTextColor: "#14301a"
    lineColor: "#7f9483"
    fontSize: "15px"
  flowchart:
    padding: 6
    nodeSpacing: 14
    rankSpacing: 18
---
flowchart TB
  accTitle: How Thea is built
  accDescr: the contract says what must be checked and what counts as proof, one core resolves the file, selects its gates, runs the checks and records the verdict, and the CLI, MCP, hooks with CI and the TheaOS all reach that one core
  R[contract · atlas.yaml<br>what counts as proof] --> C[one core: resolve, gate,<br>check, record the verdict]
  C --> doors
  subgraph doors [ ]
    direction TB
    L[CLI<br>commands] ~~~ H[hooks · CI<br>commit, merge]
    P[MCP<br>agent tools] ~~~ B[TheaOS<br>results, history]
  end
  classDef core fill:#cfe9d2,stroke:#4f9a58,color:#103d17
  class C core
  classDef band fill:none,stroke:#6f9f73,stroke-dasharray:4 3
  class doors band

$ thea gate scripts/doctor.py
1. formatter: ruff format --check scripts/doctor.py
2. compiler_or_typechecker: python3 -c 'import ast,sys; [ast.parse(open(f, encoding="utf-8").read(), f) for f in sys.argv[1:]]' scripts/doctor.py
3. unit_tests: pytest

Adapters: Claude Code, Codex, GitHub Copilot, Cursor/Grok Bot, OpenCode, Hermes, VS Code, TheaOS, llms.txt and MCP; git hooks and Actions cover builds (all runtimes).

Thea verifies development work; it does not replace its framework or toolchain (limits).

Quickstart

# no checkout
uv tool install thea-software && thea doctor
# or, editable
git clone --depth 1 --branch v3.57.1 https://github.com/HLIntel/thea-software ~/thea && uv tool install --editable ~/thea && thea doctor

cd ~/thea
thea port scripts/doctor.py   # route, gates, lessons
thea gate scripts/doctor.py   # what proves a change
thea verify                   # exit 0 only if all PASS

Read-only MCP: thea-mcp. No-shell chat: CHAT.md. Add Thea to another repository: CONSUMING.

TheaOS preview

TheaOS puts engines, changes, verdicts and failures in one workspace. The CLI is public; desktop is preview: request access (no secrets or private code). Limits.

$ thea port scripts/doctor.py --line
◉ scripts/doctor.py │ ⠟backend │ python │ ⌂scripts │ ✓3 │ ⚠1 │ → thea gate scripts/doctor.py
$ thea port scripts --line
◎ scripts │ ⠟121 │ ⌂scripts │ → thea brainstorm
$ thea port . --line
○ . │ ⠟149 ⠿4 ⠁3 │ → thea check

What it measurably buys

Recorded instruments prove routing and refusals, not end-to-end task success (limits).

With Thea the model sees what thea gate prints; blind it sees only the language names.

Right answers, with Thea vs blind (abtest.py v3.49.0, 76 questions per Claude model)

• Opus: 100% vs 41%; 90% fewer tokens.

• Sonnet: 100% vs 39%; 90% fewer tokens.

• Haiku: 100% vs 39%; 91% fewer tokens.

• Claude Code start-up: 221 tokens (CLAUDE.md and its imports).

• All 8 models (4 providers, 423 trials, v2.28.0 / v3.49.0): 99% vs 53% (95% intervals 98–100, 49–58); weakest 97%; a random guess 2.8%.

Beyond routing (blind → with Thea, taskbench.py v2.29.0)

• Name a failure from its symptom: Opus 93% → 100% · Sonnet 57% → 100% · Haiku 64% → 96%
• List the checks a change needs: Opus 12% → 100% · Sonnet 12% → 100% · Haiku 0% → 100%
• Spot a line the build refuses (coin flip: 50%): Opus 60% → 100% · Sonnet 60% → 100% · Haiku 40% → 100%
• Hand off with the right checks (schema only → with Thea, workflowbench.py): Opus 0/6 → 6/6 · Sonnet 0/6 → 6/6 · Haiku 0/6 → 6/6
• Not measured: visual design, open-ended strategy, arithmetic — nothing declares a right answer.

Failures caught

• 34/34 planted breaks refused at commit, in 26 of 42 languages; 11 have an example not yet trialled, 5 none (enforce.py v3.57.0).
• 545 mistake kinds planted in the tests, each refused.
• 116 failure shapes recorded from real runs: 200 sightings, 45 recurred, 96 now guarded.
• 245 refusals in daily use (26 shapes, 166 re-fired); verify 21 pass / 40 fail; 46/48 lands armed; 139 lessons shown (agents.py --field v3.54.0).
• 24/24 solo commits clean with or without the hook; a planted broken commit is refused.
• 6 agent controls block, never warn: narrow_tools, sandbox, budget, approval, effects, audit.

Cost

• 1,734 tokens read before routing; 196 more documents (608 KiB) load only when a route names one.
• 89% fewer tokens than pasting every tool list; 50% fewer than blind.
• 10 KiB install: 1 module, 1 dependency.

Coverage

• 378 language × check pairs (42 × 9), all answered: 146 by a command, 232 by a declared no tool, 0 silent.

Agent contract

• Route: thea port <file>, or parse .agent/bootstrap.json; load only its names.
• Automate: add --json; records follow the output schema.
• Before shell: thea shell --json "<cmd>"; exit 3 means its verdict would be misread.
• Land: python scripts/branchstate.py --land; check thea landed <branch> before deletion.
• Judge and report: use the judgment rungs; file breaks with the thea skill.

Counts, computed

Generated on every build; check refuses drift. Machine-readable: .agent/facts.json.

• 401 tool entries — across 42 manifests and 5 kinds, validated against tools/tools.schema.json
• 334 agreement edges — each a file tied to the declaration it answers for
• 81 instruments — each stating what it proves, what it does not, and what closes the gap
• 8 change classes — and 14 task profiles, in atlas.yaml
• 121 harness Python files — every one held by lint · format · typecheck
• 3.57.1 contract version — VERSION, asserted in 8 other files

Find your way

• Every document: docs index · wiki
• Languages: atlas · routing · verification
• Agents: harness · .thea · runtimes
• Why a rule: thea why · thea failures · instruments
• Security: policy · OpenSSF · contributing

Project

Version tracks the contract, not content (versioning). Built by HLIntel LLC, public on purpose (about). Contributions pass thea verify. MIT License.