Spec · CHG-2026-014907

change_id: CHG-2026-014907
risk_class: R2
autonomy_tier: A2
controls: ['TPR-05', 'TRC-01', 'CHG-04']
data_classification: public
originator: olaf@freundcloud.com
agent_identity: svc-agent-platform
model_route: gateway/tier-balanced
supersedes: None

Requirements

R1 — flake.nix pins the toolchain

Python 3.12 with the service’s dependencies, plus just, make, git, gh, jq and ruby for previewing the site. nix flake check builds the shell, so a broken environment is caught by CI rather than by a presenter.

devenv.nix declares the same toolchain for people who use devenv, and says in its own header that flake.nix is canonical — a second environment definition that claims equality is how the two come to disagree.

R2 — justfile orchestrates; Makefile still defines

Every recipe that touches the loop or the gates calls make. The Makefile is what CI runs and what AGENTS.md tells the agent to run, so restating those commands in a second file would produce two definitions that drift, and the drift would surface on the day the two disagreed about what “green” meant.

just adds what make is bad at: discoverability (just lists every recipe with its purpose), arguments (just evidence DP-11), and orchestration of the demo itself.

R3 — The demo is ordered, narrated and self-checking

scripts/demo/run_demo.sh runs nine acts in the order the argument needs:

Each act prints the command before running it, so the audience sees what produced the output. A failing act sets a flag and the script exits non-zero — the demo is testable, which is the property that stops it rotting between engagements.

--fast removes the pauses for recording or CI; --live adds the GitHub act and degrades to a printed note when gh is not authenticated.

R4 — Nothing is staged

Every number the demo prints is computed during the run, against this repository. No fixture of a previous run, no recorded output, no mock. A demo that replays a good day is the same artefact as a control that reads as operating while it is not.

Policy conflicts

None identified. Stated explicitly rather than omitted: an absent section is indistinguishable from an unperformed check.

Considered: adding Nix as a repository dependency would narrow who can run this. It is therefore additive only — python -m venv .venv && make remains supported and is what CI uses, so the pinned environment is a convenience for the presenter rather than a precondition for the argument.

Verification