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81. Reserve CI workflow env: for infrastructure plumbing, not agent behavior ​

Date: 2026-07-31

Amends: ADR 0049

Status ​

Accepted

Context ​

ADR 0080 states that a per-repo or per-org override of an agent behavior knob means overriding the harness (base: composition, per ADR 0045), not the CI workflow env: block. Review of that ADR found the practice already drifting: fullsend-ai/agents#567's docs describe setting TRIAGE_AUTO_CODE via the workflow env: block, "matching the convention used for REVIEW_FINDING_SEVERITY_THRESHOLD" — but ADR 0055's own canonical example sets REVIEW_FINDING_SEVERITY_THRESHOLD in the harness's env.sandbox, not the workflow file. Nothing had stated the workflow-env path was out of bounds for behavior knobs, so nothing caught the drift.

ADR 0049 lists "CI workflow injection" as one of three delivery mechanisms for agent config vars, alongside .env files and runner_env, without distinguishing infrastructure values (credentials, project IDs, regions) from agent behavior knobs.

Decision ​

The CI workflow env: block (.github/workflows/<agent>.yml) is reserved for infrastructure plumbing — credentials, project IDs, regions, and other infrastructure values sourced from CI-native inputs (secrets, org/repo variables). Agent behavior knobs, as scoped by ADR 0080 and named per ADR 0049, are never set there. They go through harness composition instead: env.runner/env.sandbox defaults live in the canonical harness, and a per-repo or per-org override edits those defaults via base: composition (ADR 0045).

The one exception: a value that can only be computed at CI runtime — derived from github.event.*, a build matrix variable, or a secret that cannot be expressed as static harness data — may be set in the workflow env: block even if it configures agent behavior. This ADR does not try to enumerate every such case up front; a genuine new one can be added here by minor annotation as it turns up.

This narrows ADR 0049's "CI workflow injection" delivery mechanism: it remains valid for infrastructure vars and CI-runtime-only values, not for static agent behavior defaults.

Consequences ​

  • fullsend-ai/agents#567's docs need correcting: TRIAGE_AUTO_CODE's override path is harness composition, not CI workflow env: — the precedent it cited was itself non-conformant. The fullsend-ai/agents repo's own docs/review.md carries the same non-conformant guidance for REVIEW_FINDING_SEVERITY_THRESHOLD that this PR fixed in fullsend's copy, and needs the equivalent fix.
  • CODE_ALLOWED_TARGET_BRANCHES: '' is still hardcoded in reusable-code.yml/reusable-dispatch.yml's workflow env: block, even though ADR 0053 already decided this value belongs in the harness's runner_env, not the workflow YAML. It's a pre-existing non-conformance this ADR's rule makes explicit; removing it from the workflow files is a follow-up, not part of this decision.
  • New agent behavior knobs get one documented override path (harness base: composition), removing the ambiguity between three candidate mechanisms.
  • A workflow env: entry that sets an agent behavior default, and isn't one of the CI-runtime-only exceptions, is a signal the knob was placed in the wrong layer.