Subagents now run on native Pi sessions, so everyday delegation has fewer moving parts and less process-launch fragility. Workflow progress is easier to scan, with compact lane summaries and clearer supervisor messages in the parent session. Model selection is also safer: missing, excluded, or dynamically registered provider models now produce the right outcome instead of silently falling back or failing before provider setup completes.
Highlights:
- Native Pi-session subagents replace spawned
pichild processes. - Workflow status is easier to read with compact lane summaries and better supervisor cards.
- Model selection now fails clearly when configured candidates are unavailable.
- Managed worktrees support validated
baseRefvalues and safer per-project nesting. - Background children can use provider-extension models reliably, including router-style dynamic providers.
Need to know:
| Affected users | Change |
|---|---|
| Agents that need MCP tools or provider-extension models | Use background children. Foreground children run in-process and no longer load ambient extensions. |
| Package import users | pi-subagents/pi-args is now pi-subagents/child-tool-plan.
|
| Custom Pi binary users | PI_SUBAGENT_PI_BINARY now applies only to Herdr project panes and the profile model probe.
|
Full changelog:
[0.65.0] - 2026-09-04
Highlights
- Subagents now run through native Pi sessions instead of spawning separate
piprocesses, making delegation simpler and less fragile. - Workflow status is easier to scan with compact lane summaries and clearer supervisor messages.
- Model selection fails clearly when configured models are unavailable, instead of silently using a provider default.
- Managed worktrees are safer and more flexible, with validated
baseRefsupport and per-project nesting. - Background children can use provider-extension models reliably, including dynamically registered models such as router providers.
Added
- Include sanitized model, provider, reason, and expiry details when no usable subagent model candidates remain. Thanks @AlexKucera for #1841.
- Allow managed worktrees to start from a validated
baseRefinstead of always usingHEAD. Thanks @jaudiger for #1842.
Changed
- Run subagents as native Pi
AgentSessions instead of spawnedpiCLI processes (#1844). Foreground children run in the parent process, and background children run in the detached runner. - Foreground children no longer load ambient extensions. Use background children for agents that need MCP tools or provider-extension models. Background children require Pi from the installed
@earendil-works/pi-coding-agentpackage, not a standalonepibinary. - Rename package subpath
pi-subagents/pi-argstopi-subagents/child-tool-plan;PI_SUBAGENT_PI_BINARYnow applies only to Herdr project panes and the profile model probe. - Replace collapsed async workflow role summaries with a compact lane view while keeping full details available when expanded (#1827).
- Add
contact_supervisorto the bundled reviewer and scout tool allowlists without adding mutation tools (#1846).
Fixed
- Drop only malformed persisted model-exclusion entries and rewrite the cleaned cache.
- Stop live workflow children when a run-level stop targets an in-memory async workflow controller.
- Fail closed when a fallback-only model configuration resolves no launch candidates. Thanks @AdenosineTP for #1853.
- Resolve native child models after child extensions register provider models. Thanks @mystery4f for #1855.
- Ignore stale authentication-related model exclusions after Pi's
auth.jsonis refreshed, while preserving quota, rate-limit, overload, and model-unavailable exclusions. Thanks @wesleyfei1 for #1835. - Show native supervisor requests and outbound replies as bounded TUI cards in parent sessions (#1845).
- Suppress stale async supervisor-request notices after the native request has already been answered (#1838). Thanks @VladimirGVP.
- Flush async workflow result assembly after session replacement when every child is already terminal, without permitting stale-context launches (#1833). Thanks @redcomet168.
- Accept calendar/platform
claude --versionoutput during Claude Code adapter preflight while retaining required launch-flag validation. Thanks @drouhard. - Show passive local command availability for external CLI agents in capability listings without replacing launch preflight (#1829). Thanks @drouhard.
- Nest native managed worktrees under per-project directories while preserving unsafe-location checks (#1831). Thanks @moofone.