ADR-0172 - Reversible harness economy setup

Context

Skills load on demand. They cannot govern routine chat before activation. Codex, Claude Code, and OpenCode each expose user-level instruction files, but their paths and precedence differ [CODEXGLOBAL] [CLAUDEDIR] [OPENCODERULES]. npx skills installs skills; it does not install a global interaction policy.

The CLI currently has one read-only verb. Global setup therefore requires a deliberate boundary change, not mutation hidden inside package or skill installation.

Decision

1. Add explicit setup plumbing. suspec setup <harness>... installs, checks, previews, or removes the economy policy for explicit codex, claude-code, and opencode targets. It never detects or guesses targets and never reads stdin.
2. Human authority survives convenience. Detection, dry-run, and check are non-mutating. Install and removal require target-specific owner approval plus --yes.
3. One canonical payload, generated runtime bytes. corpus/policy/economy.md owns the contract. The CLI checks in a generated module with the current bytes, source digest, version, and retained recognized version/hash pairs. Source and packaged binaries consume the same generated module.
4. Own fragments, not files. Setup mutates only marked Suspec spans in documented user-level instruction files. It refuses drift, links, special files, foreign owners, unsafe paths, ambiguous precedence, and unrecognized payloads. Removal restores the exact original bytes.
5. Be honest about enforcement. --check proves user-level installation and unambiguous documented precedence. Project, managed, and separately combined instructions can override it. Setup never claims hard enforcement or adversarial same-user filesystem security.
6. Keep checking separate. suspec check, its contract, and its exit meanings do not change. Setup has its own versioned JSON envelope. MCP exposes no setup, storage, or mutation surface.
7. Touch no repository. Setup resolves only fixed user-level locations under the home directory. It adds no registry, daemon, telemetry, hook, output style, project file, or cleanup service.

Narrowed decisions

• ADR-0140: skills remain the workflow product; setup is non-authoritative communication-policy installation, not a method carrier.
• ADR-0143 and ADR-0165: check remains path-explicit and read-only; the CLI gains one isolated user-setup verb.
• ADR-0151: setup creates no agent, role, projection, or artifact.
• ADR-0169 and ADR-0170: the no-runtime default stands for methods; witnessed global waste justifies this narrow installer.

Consequences

• Full local installation has three explicit parts: CLI, skills, and economy setup.
• The checker contract and MCP remain boring. Good.
• Unsupported or ambiguous harness states fail closed instead of receiving a confident lie.

Status

Accepted (2026-08-08). Narrows ADR-0140, ADR-0143, ADR-0151, ADR-0165, ADR-0169, and ADR-0170.