feat: zcode (z.ai GLM-5.3) worker with first-run key provisioning (2.9.0)

[mariuszkreft]

Adds z.ai's GLM Coding Plan as a first-class m2herd worker, following the prime precedent (#18).

Design decision: claude binary, z.ai endpoint

z.ai ships no CLI. ZCode is a desktop app (DMG installer, GUI-only); the npm zcode-* packages are unofficial. The path z.ai documents for a GLM Coding Plan in a terminal is Claude Code pointed at their Anthropic-compatible endpoint (https://api.z.ai/api/anthropic), with the sonnet/opus tier names mapped to GLM models.

So zcode runs the claude binary with the same auto-approve flag, plus a sourced env file. This is not a shortcut — it's what makes everything else free: session resume, the --output-format json envelope, report salvage, token parsing, and herdr's claude integration (authoritative pane lifecycle, not heuristic like prime) all work unchanged. --model sonnet (headless default, now shared with zcode) resolves to glm-5.3[1m] (1M context) server-side.

First-run key

First --agent zcode dispatch prompts once, silent input, before any worktree or pane is created; stores ~/.config/m2herd/zai.env mode 600; reused forever after. Resolution order: existing file → $ZAI_API_KEY → TTY prompt. Non-interactive runs never hang — they exit with the one-liner that fixes it. Overrides $M2HERD_ZAI_ENV, $M2HERD_ZAI_MODEL, $M2HERD_ZAI_HAIKU_MODEL.

Secret hygiene

The key is sourced by the spawned worker (set -a; . <file>; set +a), never herdr agent start --env (which would put it in this process's argv) and never interpolated into a command line. It cannot appear in ps, pane scrollback, overview.json, or --dry-run output — asserted in testing (0 occurrences).

The agent start last-resort fallback wraps the worker in /bin/bash -lc for the same reason: execing the binary directly would silently run a zcode worker against Anthropic instead of z.ai — wrong endpoint, wrong quota, confusing auth failure.

Verification

• bash -n both scripts; m2herd selftest PASS; hooks/smoke.sh 36 passed, 0 failed
• config set workers.agent zcode accepted; bogus rejected (also fixes the error message, which never listed prime)
• --dry-run dispatch for all three spawn paths (headless / pane split / agent-start fallback) carries the env; --agent claude dispatch byte-identical to before
• Caught in review-by-testing: --model '' (the sonnet default was claude-gated) — fixed

Not covered

No live call against a real GLM Coding Plan — that needs a key. First real dispatch is the remaining verification step.

🤖 Generated with Claude Code