fix(pi-plugin): resolve the OMP host CLI via bin.omp — @oh-my-pi/pi-coding-agent declares no bin.pi

[Qiiks]

Problem

On OMP (oh-my-pi) hosts without a standalone pi install, every Magic Context subagent — historian, dreamer, recomp, wrapup, upgrade, sidekick — fails at spawn:

│ ⚠ subagent run failed (spawn_failed): Executable not found in $PATH: "pi"

This surfaced as /ctx-status reporting spawn_failed and the historian never running (context compaction silently dead) after the user removed Pi.

Root cause

resolvePiInvocation positively identifies the OMP host: it walks up from process.argv[1] and matches package names in PI_CODING_AGENT_PACKAGE_NAMES, which includes @oh-my-pi/pi-coding-agent (subagent-runner.ts:44-47). But resolvePiBin then only accepts bin.pi:

typeof (bin as Record<string, unknown>).pi === "string"
    ? (bin as Record<string, string>).pi
    : undefined;

OMP's package manifest declares bin: { omp: "dist/cli.js" } — there is no bin.pi — so resolution returns null for a package the resolver just positively identified. The fallback cascade then misses item by item (generic bun.exe runtime → skip; no bundled @earendil-works/pi-coding-agent peer → skip; no pi/pi.cmd on PATH → miss) and the final fallback spawns bare "pi".

Verified against a real OMP 18.1.4 install: @oh-my-pi/pi-coding-agent/package.json → "bin": {"omp": "dist/cli.js"}.

Fix

resolvePiBin accepts the omp bin key after pi. Pi hosts (manifests with bin.pi) resolve identically; OMP hosts now resolve execPath + [realpath(dist/cli.js)] — the same "re-invoke the exact host CLI" strategy the resolver already prefers, and cross-platform-safe per the existing design notes (no shell, containment guard, realpath canonicalization all unchanged).

Verification

• With a fixture mirroring OMP's real layout (@oh-my-pi/pi-coding-agent, bin: {omp: "dist/cli.js"}), the patched resolvePiInvocation returns {command: <bun>, prefixArgs: [<realpath>/dist/cli.js]} and the old code returned the bare-pi fallback.
• The resolved invocation smoke-runs: bun <OMP>/dist/cli.js --version → omp/18.1.4, exit 0.
• Full packages/pi-plugin suite (915 tests): failure set byte-identical before and after the change (23 pre-existing environment-specific failures on Windows — symlink-creation EPERM in test fixtures and host-PATH leakage — reproduced on pristine master and on the v0.41.1 tag; the change introduces no new failures).
• tsc --noEmit clean.

Notes

• The same one-line predicate exists in the bundled dist/ output; a patch release is sufficient for users (no manifest/config changes required).
• Reproduction context: Windows 11, OMP 18.1.4, MC 0.41.2 (@cortexkit/pi-magic-context), Pi not installed.

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Summary by cubic

Fixes Magic Context subagent spawn failures on OMP hosts without a standalone pi install. resolvePiBin now uses OMP’s bin.omp entry instead of falling back to bare pi; hosts declaring bin.pi behave unchanged.

• Adds regression coverage for @oh-my-pi/pi-coding-agent, which declares only bin.omp.
• Preserves realpath canonicalization, package-root containment, and fallback ordering; no manifest or config changes are required.

^{Written for commit 31b7002. Summary will update on new commits.}

Greptile Summary

The PR fixes hidden child-agent startup on OMP-only installations by resolving the host CLI from bin.omp while retaining bin.pi precedence and existing path-containment checks.

• Extends package CLI resolution to recognize OMP’s declared executable.
• Adds an OMP-specific package fixture and regression assertion for the resolved invocation.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
packages/pi-plugin/src/subagent-runner.ts	Adds bin.omp as the fallback package-declared CLI after bin.pi, preserving existing canonicalization and containment validation.
packages/pi-plugin/src/subagent-runner.test.ts	Adds an OMP-only package fixture and verifies that the resolver invokes its canonical dist/cli.js path through the current runtime.

_{Reviews (2): Last reviewed commit: "test(pi-plugin): cover the bin.omp OMP-h..." | Re-trigger Greptile}

Context used:

• Knowledge Base — Pi plugin runtime

[greptile-apps]

OMP branch lacks regression coverage

The new bin.omp selection path has no committed fixture or assertion, so a later resolver change can restore the bare-pi fallback for OMP-only installations without the test suite detecting that all hidden child-agent workflows are broken.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

[Copilot]

🟢 Approval recommended

The change is small, targeted, and aligns with the PR description; only minor formatting nits were identified.

Pull request overview

Updates Pi CLI resolution so Magic Context subagents can spawn correctly on OMP (oh-my-pi) hosts where the host package exposes its CLI via bin.omp instead of bin.pi, preventing fallback to a missing pi executable.

Changes:

• Extend resolvePiBin to accept bin.omp (in addition to bin.pi) when selecting the host CLI entrypoint.
• Update the function doc comment to describe the Pi vs OMP bin key difference and the containment/realpath guard behavior.

File summaries

File	Description
packages/pi-plugin/src/subagent-runner.ts	Adjusts package bin resolution to recognize OMP’s bin.omp, avoiding PATH-based pi fallback on OMP-only installs.

Review details

Suppressed comments (1)

packages/pi-plugin/src/subagent-runner.ts:183

• There are two consecutive blank lines after if (!binEntry) return null; (introduced in this change). This creates a stray extra vertical gap and may violate formatting/lint rules if the repo enforces them.

	if (!binEntry) return null;


	const packageRoot = resolvePath(found.dir);

• Files reviewed: 1/1 changed files
• Comments generated: 1
• Review effort level: Lite

---

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[cubic-dev-ai]

1 issue found across 1 file

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="packages/pi-plugin/src/subagent-runner.ts">

<violation number="1" location="packages/pi-plugin/src/subagent-runner.ts:162">
P2: Add a regression test with an OMP-only manifest (`bin.omp`) that asserts the resolver returns the host invocation, so this branch cannot regress to the bare `pi` fallback unnoticed.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[cubic-dev-ai]

P2: Add a regression test with an OMP-only manifest (bin.omp) that asserts the resolver returns the host invocation, so this branch cannot regress to the bare pi fallback unnoticed.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At packages/pi-plugin/src/subagent-runner.ts, line 162:

<comment>Add a regression test with an OMP-only manifest (`bin.omp`) that asserts the resolver returns the host invocation, so this branch cannot regress to the bare `pi` fallback unnoticed.</comment>

<file context>
@@ -157,16 +159,27 @@ function resolvePiBin(
-					typeof (bin as Record<string, unknown>).pi === "string"
-				? (bin as Record<string, string>).pi
-				: undefined;
+	const binKeys = ["pi", "omp"];
+	let binEntry: string | undefined;
+	for (const key of binKeys) {
</file context>

[Qiiks]

Addressed all three review findings in 31b7002:

1. Regression test (greptile + cubic, P2) — added "resolves the OMP host CLI via bin.omp", a fixture with @oh-my-pi/pi-coding-agent declaring only bin: {omp: "dist/cli.js"}, asserting resolvePiInvocation returns {command: execPath, prefixArgs: [realpath(dist/cli.js)]} instead of the bare-pi fallback. The fixture helper (writePiCliFixture) now takes a variant: "pi" | "omp" so both package layouts are covered by the same helper.
2. Style (Copilot) — flattened the string-bin condition to a single line; restructured the object-bin branch into a single objectBin binding.
3. Stray blank line (Copilot, suppressed comment) — removed the double blank after if (!binEntry) return null;.

Verification: new test passes (1 pass/0 fail with -t "OMP host CLI"), tsc --noEmit clean, and the full packages/pi-plugin suite failure set remains byte-identical to pristine master (the 23 pre-existing Windows environment failures noted in the PR description — symlink-EPERM fixtures and host PATH leakage, reproduced on the v0.41.1 tag).

[magic-alfonso]

Verified and landed. The registry manifest for @oh-my-pi/pi-coding-agent 18.1.4 is bin: { omp: "dist/cli.js" }, and our v0.41.1 launcher resolution accepted only bin.pi, so every subagent spawn on an OMP host without a standalone pi fell through to the bare-pi fallback — a regression we shipped, and your diagnosis was exact.

Your commit is on master with your authorship (cherry-picked as 3508f7bb, merged in 31deb406), followed by a commit adding the regression coverage greptile and cubic asked for: an OMP-only manifest fixture asserting the host invocation (proven red against the previous resolver — it returned the bare pi fallback with the script-detection miss), plus the bin.pi, string-bin, and neither-key cases. The two formatting nits are folded in.

This ships in v0.41.2 with a credit in the release notes. Closing the PR since GitHub cannot mark a cherry-picked merge as merged; the change is in.