# Runner probes **Not a drill.** A drill rehearses the release doors on a disposable repo and ends. This is the opposite shape: one **standing** repo that exists so that runner-only facts can be measured on demand, and it is **never archived**. `heavy-duty/ceremony-runner-probe` — private, standing, reset between probes. Ruled by the operator as option (A) of ceremony#202 (#5631). ## Why a standing repo, when drills are disposable Some facts are only true inside Actions, under the token Actions injects, and no local harness or PAT can reproduce them. The worked example is ceremony#192: ``` DELETE /issues/{n}/labels/{id} -> 500 under ${{ github.token }} in a workflow DELETE /issues/{n}/labels/{id} -> 204 under a maintainer PAT, same call ``` A probe that runs anywhere else passes and proves nothing. Before this venue existed the answer was "un-archive a drill repo", which was requested three times in two days across two issues and never became anything — the three drill repos (`ceremony-drill-0.4.1`, `-0.4.1-final`, `-191`) are all archived, and each was minted for one probe and then wanted again. ## The disposal rule above does NOT apply here The rehearsal section says the builder archives the scratch repo and the operator deletes it. **That rule is for drills.** Archiving this repo defeats its entire purpose, and it is the failure mode the three archived drill repos demonstrate — each was archived correctly, by the rule, and each then had to be un-archived or replaced. So: never archive it, never delete it, and if you find it archived, un-archive it rather than minting a fourth one. ## Standing it up is the operator's step Bot identities cannot create repositories in `heavy-duty`. Measured 2026-08-05 with a fleet identity holding the `repo` scope: ``` POST /api/v1/orgs/heavy-duty/repos -> 403 "not allowed to create repository in organization" POST /api/v1/user/repos -> 201 (personal namespace only) ``` This is the same shape as the drill delete: a deliberate permission boundary, not a misconfiguration. Do not retry it, and do not work around it by putting the venue in a personal namespace — **not because a personal namespace is proven unable to reach the org's runner** (that was not measured; the probe repository above was deleted immediately, so nothing about runner or secret reach was established), but because @andres ruled an **org-owned standing venue** (#5631). A personally-owned repo is a different thing from the one that was decided on, and cannot satisfy #202's named acceptance target. If runner or secret reach turns out to matter, measure it once the venue exists rather than assuming it here. ## Running a probe 1. Reset the repo to a clean state — the probe's own fixtures only, no leftovers from the last one. A probe that inherits state is a probe whose result you cannot attribute. 2. **Arm it against the candidate** (below) — two layers, candidate code and armed workflow — if the probe is about ceremony's own machinery rather than about a bare API call. 3. **Run it as an Actions job under `${{ github.token }}`.** This is the whole point of the venue and the one step that cannot be shortcut. A `curl` from a laptop with a PAT answers a different question — see the 204/500 split above — and a probe run that way is worse than no probe, because it produces a confident wrong answer. 4. **The job writes its raw results into an issue in the PROBE repo** — `heavy-duty/ceremony-runner-probe` — not into ceremony. Logs age out; ceremony#192's run 701 survived only because the job wrote its findings into an issue it created. 5. **A human then records the probe issue's URL and the Actions run number on the ceremony issue the probe serves.** That hop is deliberate and is the whole of the boundary: the probe workflow holds no credential and no code path that can write to `heavy-duty/ceremony`, so "the probe reports its findings" and "the probe cannot touch the live board" stay compatible rather than contradicting each other (@codex-reviewer-andresmgsl, #202 review). ## Arming a candidate ref A probe that exercises ceremony's own machinery needs the candidate tree reachable from a `uses:` line. This is the fork-ref shape `drills/README.md` step 2 points at, written out — and it has **two layers**, which is the part that is easy to get wrong and impossible to fix afterwards. **Why two.** The candidate's own workflows contain `repository: heavy-duty/ceremony` beside `ref: ${{ env.CEREMONY_SELF_REF }}`, so they must be rewritten to point at the fork and at the candidate. But rewriting them **creates a new commit**, and a commit cannot contain its own object ID. A single-layer arming is therefore self-referential: pin the callers to the pre-rewrite SHA and they load the *unarmed* workflows; pin them to the post-rewrite one and you are asking a commit to embed itself (@codex-reviewer-andresmgsl, #202 review). So: | layer | what it is | what it carries | |---|---|---| | **candidate code SHA** | the immutable tree under test | `actions/`, `lib/` — untouched | | **armed workflow SHA** | a small child commit on top of it | workflows rewritten to the fork + `CEREMONY_SELF_REF` = the candidate code SHA | ### The procedure 1. **Push the candidate tree** to a fork under the identity that will run the probe — one branch, `/ceremony@probe-` — and record its SHA. Steps 1 and 2 advance the tip of that **same** branch; there are two commits, not two branches. That is the **candidate code SHA**. Never create a branch on `heavy-duty/ceremony` named like a tag: it shadows that tag for every consumer until somebody remembers to delete it. 2. **Commit the arming on top of it.** In that same fork branch, rewrite every workflow carrier — `repository:` → `/ceremony`, and both `CEREMONY_SELF_REF` values → the **candidate code SHA** from step 1. Record the resulting SHA. That is the **armed workflow SHA**. 3. **Pin the probe repo's callers by layer**, because they are not the same thing: - composite-action callers → `/ceremony/actions/@`; - reusable-workflow callers → `/ceremony/.github/workflows/@`, since that is the only revision whose inner checkout is rewritten. 4. **Gate the arming POSITIVELY, against the armed tree.** Absence of the old literal is not proof of correct arming: a negative grep stays green if `CEREMONY_SELF_REF` names a tag, the *armed* SHA or some other commit; if a carrier was rewritten to the wrong fork; if an executable carrier lives outside `.github`; or if a carrier simply disappeared (@codex-reviewer-andresmgsl, #202 review). So assert what each carrier **is**, not merely what it is not: ```sh fork=/ceremony ; code_sha= ; armed_sha= fail() { echo "arming incomplete: $*" >&2; exit 1; } # every self-checkout points at the fork for v in $(git grep -hoP '(?<=repository:\s)\S+' -- .github); do [ "$v" = "$fork" ] || fail "repository: $v" done # both CEREMONY_SELF_REF carriers name the CANDIDATE CODE sha n=0 for v in $(git grep -hoP '(?<=CEREMONY_SELF_REF:\s)"?\K[^"]+' -- .github); do [ "$v" = "$code_sha" ] || fail "CEREMONY_SELF_REF: $v"; n=$((n+1)) done [ "$n" -eq 2 ] || fail "expected 2 CEREMONY_SELF_REF carriers, found $n" # and in the PROBE repo: workflows pin the armed sha, actions the code sha git grep -hoP '(?<=uses:\s)\S+' -- .github | while read -r u; do case "$u" in */.github/workflows/*) [ "${u##*@}" = "$armed_sha" ] || fail "workflow caller $u" ;; */actions/*) [ "${u##*@}" = "$code_sha" ] || fail "action caller $u" ;; esac done # the negative check stays, as a cheap extra rather than as the proof ! git grep -qE '(uses:|repository:)[[:space:]]*heavy-duty/ceremony' -- .github \ || fail "canonical coordinate still present" ``` **A count, not just a comparison** — `n -eq 2` is what catches a carrier that vanished rather than being rewritten, which a per-value loop alone cannot see. 5. **Invoke the probe by the event it is about**, and record which: a `workflow_dispatch`, or the real board event under test. A probe that fires a different event than the one under test proves something else. 6. **The result issue records all of it**: the fork repository, the candidate code SHA, the armed workflow SHA, every rewritten carrier, the workflow invoked and the run number. Those are what make the result reproducible; without the two SHAs distinguished, a later reader cannot tell which tree answered. 7. **Reset removes the candidate-specific EXECUTABLE state**: the caller stubs, the probe workflow, and the fork's probe branch — whose tip carries both the candidate commit and the armed commit on top of it — so the next probe cannot inherit a pin it did not choose. **Result issues are never deleted.** They may be closed or relabelled; deleting them would recreate the expiring-log problem this venue exists to avoid. ## Who may reset it **Operator-owned until ruled otherwise.** #202's task 4 asks who may reset the venue, and creating the repo is the operator's step, so the access policy is his to set at the same time (@codex-reviewer-andresmgsl, #202 review). Two levels, deliberately separated: - **content reset** — removing probe branches, workflows and fixtures; the ordinary between-probes operation. It does **not** include deleting result issues, which are the evidence and are immutable once written (@codex-reviewer-andresmgsl, #202 review); - **archive / delete / admin** — which is where the drill rule's damage came from, and which no bot identity should hold here. If fleet identities are given push access for content reset, this section records that; until then, ask. ## What must never happen here No probe touches `heavy-duty/ceremony`'s board. No labels, no comments, no runs attributable to a probe. The venue exists so that the live board does not have to be the test fixture. ## The probes this venue owes - **ceremony#192** — that the repaired sweep actually lifts a label under the workflow token, which is the half its acceptance criteria cannot get from the hermetic contract tests. - **ceremony#205** — whether `POST /actions/workflows/{file}/dispatches` works on this instance with a valid ref and inputs. Measured so far: `GET /actions/workflows` 404s and the dispatch route answers 500 rather than a 4xx, which is not enough to port against. - A 0.6.0 consumer exercise once ceremony#198 has merged.