enhance(fleet-host): provide bare 'python' (python-is-python3) on agent hosts — 19x 'python: command not found'/24h #561

New Issue

jason.woltje · 2026-06-20T09:26:10Z

jason.woltje commented

2026-06-20 09:26:10 +00:00

Problem

Agent hosts (web1) have python3 but no bare python on PATH. Fleet agents — especially Pi/codex (gpt-5.5) sessions — frequently emit python foo.py, which fails with python: command not found (exit 127). The agent then burns a recovery turn re-issuing the command as python3.

Evidence

Nightly enhance harvest, 24h window ending 2026-06-20: ~19 occurrences across 13 distinct Pi sessions. Confirmed first-hand in transcript 019edc8a (Pi session) — python: command not found exit 127 ×2.

Caveat: the harvester cannot parse Pi/codex tool-calls precisely, so 19× is a coarse pointer, not an exact count — but the pattern is real (deep-read confirmed) and recurring across many sessions.

Why it matters (north star: wall-clock)

Each occurrence = one failed exec + one model recovery turn. Pure wall-clock waste, repeated dozens of times/day across the fleet. The fix is permanent and one-line.

Root cause

Modern distros ship python3 only; python-is-python3 is not installed. The model's prior favors bare python, so guidance alone won't fully eliminate it — the host should satisfy the common invocation.

Proposed fix

On agent hosts, install python-is-python3 (Debian/Ubuntu) or symlink /usr/bin/python -> python3. Add to the agent-host bootstrap/provisioning so new hosts inherit it.

Routing note

Filed in mosaicstack/stack as the framework/bootstrap owner (BOOTSTRAP.md covers host prereqs). If web1 host config is better owned by usc/infrastructure, please re-route — Mos to decide dispatch.

Acceptance

python --version resolves on agent hosts.
python: command not found drops to ~0 in the next nightly harvest window.

Filed by the nightly fleet-enhancement pass (enhance/ae4). New learning captured to OpenBrain (29c3307d). Merge authority remains with Mos/coordinator (AGENTS.md rule 38).

## Problem Agent hosts (web1) have `python3` but **no bare `python`** on PATH. Fleet agents — especially Pi/codex (gpt-5.5) sessions — frequently emit `python foo.py`, which fails with `python: command not found` (exit 127). The agent then burns a recovery turn re-issuing the command as `python3`. ## Evidence Nightly enhance harvest, 24h window ending 2026-06-20: **~19 occurrences across 13 distinct Pi sessions**. Confirmed first-hand in transcript `019edc8a` (Pi session) — `python: command not found` exit 127 ×2. Caveat: the harvester cannot parse Pi/codex tool-calls precisely, so 19× is a **coarse pointer**, not an exact count — but the pattern is real (deep-read confirmed) and recurring across many sessions. ## Why it matters (north star: wall-clock) Each occurrence = one failed exec + one model recovery turn. Pure wall-clock waste, repeated dozens of times/day across the fleet. The fix is permanent and one-line. ## Root cause Modern distros ship `python3` only; `python-is-python3` is not installed. The model's prior favors bare `python`, so guidance alone won't fully eliminate it — the host should satisfy the common invocation. ## Proposed fix On agent hosts, install `python-is-python3` (Debian/Ubuntu) **or** symlink `/usr/bin/python -> python3`. Add to the agent-host bootstrap/provisioning so new hosts inherit it. ## Routing note Filed in `mosaicstack/stack` as the framework/bootstrap owner (BOOTSTRAP.md covers host prereqs). If web1 host config is better owned by `usc/infrastructure`, please re-route — Mos to decide dispatch. ## Acceptance - `python --version` resolves on agent hosts. - `python: command not found` drops to ~0 in the next nightly harvest window. --- _Filed by the nightly fleet-enhancement pass (enhance/ae4). New learning captured to OpenBrain (29c3307d). Merge authority remains with Mos/coordinator (AGENTS.md rule 38)._

jason.woltje added the fleet-enhancement label 2026-06-20 09:26:10 +00:00

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Reference: mosaicstack/stack#561