# Tandem Licensing

## Machine-readable summary

**Repository license class:** Open Core / Mixed License  
**Open-source components:** MIT, Apache-2.0, or MIT OR Apache-2.0  
**Source-available components:** Business Source License 1.1 (`BUSL-1.1`)  
**Default rule:** Each package is governed by its package-local manifest and/or package-local license file.  
**Canonical license map:** This file.

Tandem is an open-core project. Most SDK, runtime, client, local execution,
and support components are available under permissive open-source licenses.
Selected governance, plan-compilation, incident-monitoring, and enterprise
components are source-available under `BUSL-1.1`.

This repository is therefore **not governed by one blanket root license**.
The root [`LICENSE`](../LICENSE) file is a repository-level notice only. For
exact terms, use the package-by-package table below.

## Plain-language summary

- Permissive open-source components use `MIT`, `Apache-2.0`, or `MIT OR Apache-2.0`.
- Selected governance and enterprise components use `BUSL-1.1`. Evaluation,
  development, testing, source inspection, personal non-commercial use, and
  non-production proofs of concept are permitted without charge. Commercial
  production use, including internal production use and client production
  deployments, requires a separate commercial license from Frumu LTD.
- If this document, the root `LICENSE`, and a package-local manifest or license file disagree, the package-local manifest and package-local license file control for that package.

## Licensing change effective 0.7.0

The corrected Additional Use Grant in the five package-local BUSL licenses is
the policy for **0.7.0 and later**. It first shipped in the 0.7.0 release
(2026-07-15).

This change is prospective. Each released version remains governed by the
license distributed with that version; it does not revoke, replace, or modify
historical rights. In particular, **0.6.9 remains governed by its original
license terms**. Historical tags and release artifacts must not be rewritten or
deleted to imply retroactive relicensing.

## Rust SDK and Runtime Packages

The Rust SDK/runtime surface is dual-licensed under:

- `MIT`
- `Apache-2.0`

Consumers may choose either license (`MIT OR Apache-2.0`) for the packages below, unless a package-local manifest or license file states otherwise.

| Package                       | Path                                           | License             |
| ----------------------------- | ---------------------------------------------- | ------------------- |
| `tandem-ai` / `tandem-engine` | `engine/Cargo.toml`                            | `MIT OR Apache-2.0` |
| `tandem` (desktop)            | `apps/tandem-desktop/src-tauri/Cargo.toml`     | `MIT OR Apache-2.0` |
| `tandem-agent-teams`          | `crates/tandem-agent-teams/Cargo.toml`         | `MIT OR Apache-2.0` |
| `tandem-automation`           | `crates/tandem-automation/Cargo.toml`          | `MIT OR Apache-2.0` |
| `tandem-browser`              | `crates/tandem-browser/Cargo.toml`             | `MIT OR Apache-2.0` |
| `tandem-channels`             | `crates/tandem-channels/Cargo.toml`            | `MIT OR Apache-2.0` |
| `tandem-core`                 | `crates/tandem-core/Cargo.toml`                | `MIT OR Apache-2.0` |
| `tandem-data-boundary`        | `crates/tandem-data-boundary/Cargo.toml`       | `MIT OR Apache-2.0` |
| `tandem-document`             | `crates/tandem-document/Cargo.toml`            | `MIT OR Apache-2.0` |
| `tandem-enterprise-contract`  | `crates/tandem-enterprise-contract/Cargo.toml` | `MIT OR Apache-2.0` |
| `tandem-eval`                 | `crates/tandem-eval/Cargo.toml`                | `MIT OR Apache-2.0` |
| `tandem-graph-core`           | `crates/tandem-graph-core/Cargo.toml`          | `MIT OR Apache-2.0` |
| `tandem-memory`               | `crates/tandem-memory/Cargo.toml`              | `MIT OR Apache-2.0` |
| `tandem-meta-harness-eval`    | `crates/tandem-meta-harness-eval/Cargo.toml`   | `MIT OR Apache-2.0` |
| `tandem-orchestrator`         | `crates/tandem-orchestrator/Cargo.toml`        | `MIT OR Apache-2.0` |
| `tandem-wire`                 | `crates/tandem-wire/Cargo.toml`                | `MIT OR Apache-2.0` |
| `tandem-repo-intelligence`    | `crates/tandem-repo-intelligence/Cargo.toml`   | `MIT OR Apache-2.0` |
| `tandem-providers`            | `crates/tandem-providers/Cargo.toml`           | `MIT OR Apache-2.0` |
| `tandem-skills`               | `crates/tandem-skills/Cargo.toml`              | `MIT OR Apache-2.0` |
| `tandem-types`                | `crates/tandem-types/Cargo.toml`               | `MIT OR Apache-2.0` |
| `tandem-observability`        | `crates/tandem-observability/Cargo.toml`       | `MIT OR Apache-2.0` |
| `tandem-runtime`              | `crates/tandem-runtime/Cargo.toml`             | `MIT OR Apache-2.0` |
| `tandem-tools`                | `crates/tandem-tools/Cargo.toml`               | `MIT OR Apache-2.0` |
| `tandem-tui`                  | `crates/tandem-tui/Cargo.toml`                 | `MIT OR Apache-2.0` |
| `tandem-workflows`            | `crates/tandem-workflows/Cargo.toml`           | `MIT OR Apache-2.0` |

`tandem-meta-harness-eval` is an internal crate (`publish = false`) and is not
distributed on crates.io; it is listed for completeness.

## JavaScript and Python Packages

| Package                | Path                                                 | License             |
| ---------------------- | ---------------------------------------------------- | ------------------- |
| `tandem-ai`            | `packages/tandem-ai/package.json`                    | `MIT`               |
| `@frumu/tandem-client` | `packages/tandem-client-ts/package.json`             | `MIT`               |
| `tandem-client`        | `packages/tandem-client-py/pyproject.toml`           | `MIT`               |
| `create-tandem-panel`  | `packages/create-tandem-panel/package.json`          | `MIT OR Apache-2.0` |
| Tandem panel scaffold  | `packages/create-tandem-panel/template/package.json` | `MIT OR Apache-2.0` |
| `@frumu/tandem-panel`  | `packages/tandem-control-panel/package.json`         | `MIT OR Apache-2.0` |
| `@frumu/tandem`        | `packages/tandem-engine/package.json`                | `MIT OR Apache-2.0` |
| `@frumu/tandem-enterprise` | `packages/tandem-enterprise/package.json`        | `MIT OR Apache-2.0` |
| `@frumu/tandem-tui`    | `packages/tandem-tui/package.json`                   | `MIT OR Apache-2.0` |

The `@frumu/tandem-desktop` app package (`apps/tandem-desktop/package.json`) is
`private` and not published to npm, so it is not listed here.

## Source-Available / BUSL-1.1 Components

| Package                    | Path                                         | License    |
| -------------------------- | -------------------------------------------- | ---------- |
| `tandem-plan-compiler`     | `crates/tandem-plan-compiler/Cargo.toml`     | `BUSL-1.1` |
| `tandem-governance-engine` | `crates/tandem-governance-engine/Cargo.toml` | `BUSL-1.1` |
| `tandem-enterprise-server` | `crates/tandem-enterprise-server/Cargo.toml` | `BUSL-1.1` |
| `tandem-incident-monitor`  | `crates/tandem-incident-monitor/Cargo.toml`  | `BUSL-1.1` |
| `tandem-server`            | `crates/tandem-server/Cargo.toml`            | `BUSL-1.1` |

## Open-core boundary

The following components are source-available and are not OSI-approved open source:

- `crates/tandem-plan-compiler`
- `crates/tandem-governance-engine`
- `crates/tandem-enterprise-server`
- `crates/tandem-incident-monitor`

All other packages listed above are intended to be used under their stated
permissive open-source licenses unless a package-local manifest or license file
states otherwise.

The BUSL-1.1 components protect Tandem's commercial governance layer. The
permissive licenses keep the SDKs, clients, schemas, and the rest of the
engine source auditable and reusable under open-source terms.

### Engine binaries are mixed-license

Every distributed Tandem engine binary includes **all five** `BUSL-1.1`
components — there is no BUSL-free or governance-free engine binary. All
release artifacts (`tandem-engine` on every platform, the desktop sidecar,
`tandem-tui`, `tandem-browser`) are built with `tandem-ai/enterprise`:
enterprise routes, premium governance, and Google Drive connectors compiled
in. The hosted Linux asset (`tandem-engine-enterprise-*`, built with
`tandem-ai/enterprise-full`) differs only by adding the local-embedding
stack (fastembed/ort) — a build-weight difference, not a licensing one.

Several permissive crates depend on source-available crates directly:

- `tandem-automation` (MIT) depends on `tandem-plan-compiler`
- `tandem-eval` (MIT) depends on `tandem-incident-monitor` and
  `tandem-server` (both `BUSL-1.1`)

`tandem-server` itself was relicensed from `MIT OR Apache-2.0` to `BUSL-1.1`
effective 0.7.0: it contains substantial production governance enforcement and
composes the other protected components. Versions released before 0.7.0 remain
under the permissive terms they shipped with.

What this means in practice:

- **Running a distributed binary** is governed by the BUSL Additional Use
  Grant for the source-available components it contains. Evaluation,
  development, testing, source inspection, personal non-commercial use, and
  non-production proofs of concept are permitted without charge. Commercial
  production use, including internal production use and client production
  deployments, requires a separate commercial license from Frumu LTD.
- **Using an individual permissive crate as a library** stays under that
  crate's MIT/Apache terms. If the crate depends on a `BUSL-1.1` crate, Cargo
  pulls that dependency with its own license, and the BUSL terms apply to that
  part of your build. Each crate's manifest declares its license accurately;
  nothing is relicensed by inclusion.

This is a deliberate choice: rather than maintaining feature-stripped
BUSL-free binaries, the source-available components ship in every engine
artifact, and this section plus the per-crate license map is the disclosure
that makes the boundary clear.

These components are source-available, not open source. Their package-local
`LICENSE` files define the Additional Use Grant, production-use boundary,
Change Date, and Change License.

Current source-available license files:

- `crates/tandem-plan-compiler/LICENSE`
- `crates/tandem-governance-engine/LICENSE`
- `crates/tandem-enterprise-server/LICENSE`
- `crates/tandem-incident-monitor/LICENSE`
- `crates/tandem-server/LICENSE`

The source-available governance layer authorizes recursive and Self-Operator behavior such as agent-authored automation creation, approval-bound capability requests, lineage enforcement, and spend/review guardrails.

### Additional Use Grant (what is free vs. licensed)

The authoritative legal terms are in the five package-local `LICENSE` files.
In plain language, the grant permits without charge:

- evaluation, source inspection, security review, development, testing,
  education, training, demonstrations, and other non-production work;
- proofs of concept that are not connected to production systems, do not
  process production data, do not cause material business consequences, and
  are not relied on for ongoing business operations;
- genuine personal, educational, experimental, open-source, and other
  non-commercial uses by natural persons, including personal self-hosting; and
- agency, consultant, and systems-integrator training, demonstrations,
  integration/template development, and non-production client evaluations.

Personal or hobbyist use cannot be performed for an employer or client, process
employer, client, or customer production data, govern commercial production
systems, or form part of a commercial, managed, or client deployment. Agency,
consultant, and integrator evaluation rights similarly do not authorize a
client production deployment. A personal non-commercial workflow is not
Commercial Production Use solely because it is persistent, scheduled, or
unattended, if it continues to satisfy those personal-use limitations.

Agencies, consultants, and integrators may charge for their own consulting,
implementation, customization, and support services. That does not authorize
them to provide production access to the protected components for a client
without the required Frumu LTD commercial authorization.

A separate commercial license from Frumu LTD is required for commercial
Production Use. That includes internal operation by a commercial organization,
live business systems or data, production AI-agent governance or action
control, persistent/scheduled/unattended/business-critical workflows, client
deployments, and managed, hosted, SaaS, white-label, embedded, OEM, reseller,
or other commercial services.

Frumu LTD may offer separately authorized commercial arrangements, including
an Enterprise Pilot, a Community Production License, partner/reseller/OEM
agreements, or hosted subscriptions. Those arrangements are not a condition of
the public BUSL grant and may have their own eligibility and commercial terms.
The public grant has no automatic production exemption based on organization
size, revenue, employee count, or number of runtimes.

### Change Date policy

Each released version's `Change Date` is set to **four years after that
version's release date** (a rolling window; on the Change Date the version
converts to the Change License, `GPL-2.0-or-later OR MIT OR Apache-2.0`).
`scripts/bump-version.sh`, the PowerShell twin, and the release tag-sync path
stamp `Change Date` to run-date + 4 years in every `BUSL-1.1` `LICENSE` file
and update the labeled current source-tree date below as part of the release
version bump. The LICENSE files they discover are any `crates/*/LICENSE`
containing the BUSL-1.1 text, so newly relicensed crates are covered without
script changes.

BUSL applies separately to each version, so this licensing correction is
prospective. The corrected grant is intended to first ship in **0.7.0**;
earlier releases retain the licenses distributed with them.

**Current source-tree BUSL Change Date:** `2030-07-17`.

The `Change Date` in the shipped 0.6.9 license files is `2030-07-12`, and in
the shipped 0.7.0 license files `2030-07-15` — each release date plus four
years, per the rolling-window policy above. Before publishing any release, the
release owner should verify the current source-tree date is four years after
that release's date and use the existing release tooling to correct it if
needed. Historical license files must never be rewritten.

## License Texts

- Repository mixed-license notice: `LICENSE`
- MIT text: `LICENSE-MIT`
- Apache 2.0 text: `LICENSE-APACHE`
- Business Source License 1.1 terms: package-local `LICENSE` files in each `BUSL-1.1` component

No license in this repository grants trademark rights. See the
[Frumu LTD Trademark Policy](../TRADEMARKS.md) for use of the "Tandem" and
"Frumu" names and logos.

## Boundary and contributor review

See [Licensing Boundary and Contributor-Risk Audit](LICENSING_BOUNDARY_AUDIT.md)
for the permissive packages that currently sit near the enterprise boundary,
the factual contributor/copyright observations, and the open questions for
counsel review.

## CI Enforcement

Rust dependency license policy is enforced by `cargo deny` using
`.config/deny.toml`. License and advisory exceptions follow the process in
[`CI_SECURITY_AND_COVERAGE.md`](CI_SECURITY_AND_COVERAGE.md).

The package-by-package tables above are enforced by
`scripts/verify-license-map.mjs`, which runs in the "Validate Docs" CI job. It
fails the build if any workspace package (Rust workspace member, published
`packages/*` npm package, or `pyproject.toml`) is missing from this file,
carries a license that disagrees with its manifest, or is mapped to a path that
no longer exists. `scripts/verify-licensing-terms.mjs` verifies the protected
BUSL grants, the prospective notice, the no-loophole language, and the rolling
Change Date invariants. When you add a package or change a `license` field,
update the matching table here in the same change.

## NOTICE Guidance (Apache-2.0 users)

Apache-2.0 does not require a `NOTICE` file unless one is distributed with the work. If downstream redistributors add Apache attribution notices, they should preserve any applicable notices consistent with Apache-2.0 Section 4.

## Tandem TUI Adaptation Notes

`tandem-tui` includes tandem-local implementations adapted from design/code patterns in `codex` (Apache-2.0), including composer/editor behavior and markdown rendering strategy.

Primary adapted source references:

- `codex/codex-rs/tui/src/public_widgets/composer_input.rs`
- `codex/codex-rs/tui/src/bottom_pane/textarea.rs`
- `codex/codex-rs/tui/src/markdown_render.rs`

These adaptations are rewrites for Tandem architecture and are not line-for-line copies.