feat(agent): wire up hog (pi) as a selectable runtime adapter

[jonathanlab]

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[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 3e1aae5.}

[greptile-apps]

Comments Outside Diff (1)

1. packages/harness/src/acp.ts, line 1034-1047 (link)

   "error" mapped to "refusal" conflates error and refusal

   "error" as Pi's stop reason indicates an internal failure (gateway 5xx, malformed LLM response, tool crash), not a model content policy refusal. Mapping it to "refusal" surfaces to the client as "model declined to answer," hiding the real cause and making it appear as a deliberate refusal when the agent simply crashed. Any stop reason not explicitly covered by the ACP spec is probably safer mapped to "end_turn" (or a dedicated error state if the protocol supports one) so clients don't misclassify infrastructure failures as safety blocks.

_{Reviews (1): Last reviewed commit: "feat(agent): wire up hog (pi) as a selec..." | Re-trigger Greptile}

[greptile-apps]

getClaudeModelRecency sort applied to mixed Claude + OpenAI models in the hog adapter

getClaudeModelRecency uses Claude model naming conventions. For OpenAI model IDs (gpt-*, o*), it almost certainly returns the same default value, so all OpenAI models will cluster together in an undefined order. Sorting the hog adapter's mixed catalogue is fine, but a sort key that is meaningful for all model families would be clearer intent.

Suggested change

	// The gateway returns models in an arbitrary order. Sort Claude and hog
	// models oldest-to-newest so the picker is deterministic and the newest
	// model lands at the end of the list, closest to the trigger.
	if (adapter !== "codex") {
	// The gateway returns models in an arbitrary order. Sort Claude models
	// oldest-to-newest so the picker is deterministic; OpenAI models returned
	// by the hog adapter have no comparable recency function and will cluster
	// at the same sort key (keeping their gateway order relative to each other).
	if (adapter !== "codex") {

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[jonathanlab]

Fixed: updated the comment to accurately describe the behavior — OpenAI models clustering at the same sort key (no comparable recency function) is expected, not a bug, so this is a clarity fix rather than a logic change.

[greptile-apps]

getOtherAdapter name no longer describes the function's behaviour

After this change the function cycles through a three-element ring rather than returning a binary "other." Calling it getNextAdapter (or getNextAdapterInCycle) would match what the code actually does and avoid confusion for future readers.

Suggested change

	function getOtherAdapter(adapter: AgentAdapter): AgentAdapter {
	return adapter === "claude" ? "codex" : "claude";
	const index = ADAPTER_CYCLE.indexOf(adapter);
	return ADAPTER_CYCLE[(index + 1) % ADAPTER_CYCLE.length];
	}
	function getNextAdapter(adapter: AgentAdapter): AgentAdapter {
	const index = ADAPTER_CYCLE.indexOf(adapter);
	return ADAPTER_CYCLE[(index + 1) % ADAPTER_CYCLE.length];
	}

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!

[jonathanlab]

Fixed: renamed to getNextAdapter, and the local variable/prop usages (otherAdapter -> nextAdapter) for consistency.

[jonathanlab]

Addressed the greptile P1 finding: piStopReasonToAcp in packages/harness/src/acp.ts no longer maps pi's "error" stop reason to ACP's "refusal" — that conflated an internal failure (gateway 5xx, malformed response, tool crash) with a deliberate model content-policy decline. Since ACP has no dedicated failure stop reason, it now maps to "end_turn", the neutral choice among what the protocol actually offers.