Pi 1.4.0 adoption

Scope

Upgrade Agent Runtime's pi-agent-core, pi-ai, and pi-coding-agent, plus Desktop's pi-ai and pi-mcp, to exactly 1.4.0. Keep the Pi release group aligned through the lockfile and exact release-age exclusions. No Host protocol, database schema, persisted provider endpoint, permission policy, extension VERSION marker, or storage ownership changes.

Official release notes: Pi 1.4.0, pi-ai changelog, pi-agent-core changelog, and pi-coding-agent changelog.

Compatibility work

• Rebase the three pnpm patches onto the published 1.4.0 package layouts. Preserve hosted-search streaming, replay and estimation; bounded Anthropic OAuth handling; DeepSeek reasoning replay and endpoint-scoped capability; local request errors; and model-aware native session context estimation and image degradation.
• Adopt the new pi-ai client identity API at the agent boundary. Agent Runtime and subagents explicitly set attribution: null, which suppresses the new pi-agent-core default attribution headers while retaining pi-ai's detailed, versioned User-Agent.
• Keep Desktop's native-session and trusted-extension use of pi-coding-agent behind their existing compatibility seams. Do not expand the extension shim or change its legacy VERSION marker.
• Native Pi sessions continue to use pi-coding-agent's telemetry preference for its SDK-managed attribution headers. The Desktop-owned main and delegated agent requests explicitly suppress Pi attribution.
• Keep Desktop-owned endpoint projection, provider retry policy, MCP ownership, context projection, compaction, and session persistence unchanged.

Explicitly unchanged

• Existing user data needs no migration. No persisted format, RPC, Plugin SDK, or permission contract changes.
• The Pi 1.4.0 release's model catalog and provider adapter improvements are available through the pinned upstream package. Desktop continues to own its model catalog overlays and endpoint projection.
• pi-coding-agent remains transitional; it is not the normal Desktop agent loop, compaction engine, or durable session store.
• The Desktop main and delegated agent identity is fixed at runtime and is not persisted with provider/model configuration. Native sessions use the pi-coding-agent SDK's install-telemetry setting for its attribution headers.

Validation

Validation was run from the dedicated request worktree based on c014b32060ca2dc7ace4c83f181685a6e0140c78 (origin/main, 2026-10-28).

• Task candidate: b460e75806f433085c4915c6da4ceb57a60dd466; base main: c014b32060ca2dc7ace4c83f181685a6e0140c78. Candidate suites: pnpm --filter @pi-desktop/agent-runtime test (1,556/1,556), pnpm test:e2e:hosted-search (10/10), and PI_DESKTOP_HOST_BIN=<reused debug host binary> pnpm test:e2e:trusted-extensions (57/57). All three passed. E2E used isolated temporary profiles and fixtures, Electron 43.6.0 from the primary checkout, and the existing debug Host binary; it used no real provider credentials or live services.
• pnpm build:js, Desktop typecheck, lint, and pnpm docs:check passed.
• All 111 Agent Runtime test files passed (1,556 tests). The focused 1.4 identity/contract/runtime/subagent set passed (426 tests).
• Pi dependency and patch gates passed; all 7 patch-hash fixture tests passed.
• Hosted-search E2E passed 10/10 scenarios. Trusted-extension E2E passed 57/57 using the existing primary-checkout Electron and debug Host binaries with isolated fixture state. No real provider or live service was used.
• pnpm -r --workspace-concurrency=1 --if-present test completed with 4,550 Desktop tests passed, 3 skipped, and one failure. The OAuth assertion passes in the complete run. The unchanged composer-deep-file-search-user-path Electron fixture also fails on a detached origin/main diagnostic worktree; both runs return no rows, with different final assertions. The test and its renderer search sources are unchanged by this task.
• Rust checks were not run because no Rust source, persistence, or Host contract changed. The trusted-extension E2E reused the existing debug Host binary.

Rollback

Roll back the direct manifests, lockfile, exact release-age exclusions, three patch files, version gates, identity wiring, tests, and synchronized specs together. Never mix a patched 1.3.0 package with the 1.4.0 release group.