feat: replace single agent config with a roster, allow ad-hoc ACP agents

[liam-russell]

Type

• feat — new feature or user-visible capability
• fix — bug fix
• perf — performance improvement
• chore — dependency bump, tooling, no user-facing change
• docs — documentation only
• refactor — internal change, no behavior change

Summary

• Replaced the single configured AI agent with a named roster: add multiple agents (presets or custom commands), pick a default, and switch between them from Settings → AI Agents.
• Any agent can now be flagged as ACP-capable ("Speaks ACP") to unlock Integrated (Chat tab) mode, instead of being limited to the five hardcoded presets (Claude Code, Gemini, Codex, Kiro, Cursor) — those presets still default to ACP-capable automatically.
• Each roster agent supports its own environment variables (API keys, base URLs, etc.), so a custom or proxied agent doesn't need global env pollution.
• The agent Test button now performs a real ACP initialize handshake for ACP-flagged agents and reports the agent's name, version, and negotiated capabilities.
• Added JSON import/export of agent definitions so a team can share a working custom-agent config.
• Existing single-agent settings are migrated automatically into the new roster the first time the app reads them — no user action needed.

Why

Closes #143. The previous config only supported one agent at a time and hardcoded which commands could use Integrated/ACP mode, blocking obscure or internal ACP-speaking CLIs (Snowflake CoCo, internal wrappers, etc.) and blocking the fan-out flow (#137) from ever using more than one agent.

Screenshots / recordings

Not captured — this environment doesn't have a way to drive the packaged Electron renderer through the available browser-preview tooling (it's not a plain web app on a static port). The new Settings → AI Agents UI (roster list, per-agent edit panel with env vars/mode/ACP checkbox, Test button, Import/Export) was instead verified end-to-end via the WebdriverIO E2E suite against a real built Electron app (see Test plan) — all agent-related specs pass, including editing/saving/testing an agent row and the Integrated-mode toggle.

Breaking changes

• IPC contract: agent:get/agent:save were replaced by agent:rosterGet/agent:rosterSave (whole-roster read/write). agent:launch, agent:test, agent:acpAdapterStatus, and chat:start now take an agentId/agent-shaped argument instead of implicitly reading the single stored AgentConfig. These are internal Electron IPC channels, not a public API, but any local script poking window.api.getAgentConfig()/saveAgentConfig() directly will need to switch to getAgentRoster()/saveAgentRoster().
• Config DB: the legacy agentConfig setting key is left in place (untouched) and migrated into a new agentRoster key on first read after upgrading — no data loss, but a downgrade to a pre-roster build would silently ignore any roster edits made after upgrading (since it reads the untouched legacy key).

Test plan

• Added/updated unit tests:
  • packages/database/src/__tests__/agents.test.ts — roster persistence, defaulting, and migration from the legacy single-agent config (valid, corrupted, wrong-shape, and non-ACP-recognized-command cases).
  • app/src/main/ipc/__tests__/agent-test.test.ts — getAcpLaunchSpecForAgent (recognized preset vs. ad-hoc acp: true assertion vs. unrecognized+unflagged), plus a real end-to-end ACP initialize handshake against the minimal example agent shipped in @agentclientprotocol/sdk (no credentials needed), proving the handshake path and capability reporting actually work.
  • app/src/main/ipc/__tests__/acp-adapter-status.test.ts and __tests__/project-idea-generator.test.ts updated for the roster-based API.
• Updated E2E specs (e2e/specs/agent-workflow.spec.ts, e2e/specs/new-from-idea-workflow.spec.ts) to seed a one-entry roster instead of a single agent config, and to use the new per-row roster UI test ids.
• Ran locally and all green:
  • pnpm lint
  • pnpm typecheck
  • pnpm test (unit tests across all packages + the full WebdriverIO E2E suite, including agent-workflow.spec.ts's "agent launch workflow" and "agent settings" suites)
  • pnpm knip --exclude exports,types (no new dead code)

Deferred (per issue scope): per-fan-out-subtask agent choice (#137) and role defaults (#151) — the roster and agentId plumbing added here should make both straightforward follow-ups.

[Copilot]

Pull request overview

This PR upgrades SproutGit’s coding-agent configuration from a single stored agent to a named agent roster, enabling multiple presets/custom agents, per-agent environment variables, ad-hoc ACP capability flags, and roster-wide import/export. It updates the Electron IPC contract and wiring so agent launch, agent testing, ACP adapter status, and integrated chat mode can target a specific roster entry (or fall back to the roster default).

Changes:

• Introduces new roster types (AgentRoster, AgentRosterEntry, AgentTestInput) and extends tool test results to optionally include ACP handshake info.
• Replaces single-agent config DB storage with agentRoster (including legacy agentConfig migration), and updates IPC/preload/renderer flows to use roster APIs and agentId.
• Expands agent:test to run a real ACP initialize handshake for ACP-flagged agents and report negotiated capabilities; updates unit + E2E tests accordingly.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/types/src/tools.ts	Extends ToolTestResult with optional ACP handshake info payload.
packages/types/src/ipc.ts	Replaces single-agent IPC channels with roster channels; adds agentId plumbing to relevant calls.
packages/types/src/agents.ts	Adds roster/entry/test-input/handshake types; re-docs legacy AgentConfig as migration-only.
packages/database/src/index.ts	Re-exports new roster persistence + resolution helpers.
packages/database/src/agents.ts	Implements roster storage, legacy migration, ACP recognition helper, and agent resolution logic.
packages/database/src/tests/agents.test.ts	Updates DB tests for roster seeding, persistence, migration, validation, and resolution helper.
e2e/specs/new-from-idea-workflow.spec.ts	Seeds an agent roster for E2E instead of the legacy single-agent config.
e2e/specs/agent-workflow.spec.ts	Updates E2E agent workflow to use roster APIs, new test ids, and SPROUTGIT_AGENT semantics.
app/src/renderer/workspace/WorktreeSidebar.tsx	Updates Settings UI copy to reference “AI Agents” (plural).
app/src/renderer/settings/AISection.tsx	Updates copy to reflect roster-based agents configuration.
app/src/renderer/settings/AgentsSection.tsx	Replaces single-agent editor row with roster list UI, per-agent edit/test, per-agent env vars, import/export.
app/src/renderer/routes/workspace.tsx	Switches workspace agent gating/launch behavior to roster default agent selection and agentId launch.
app/src/renderer/routes/index.tsx	Switches HomeView “New from idea” gating to roster default agent presence.
app/src/preload/index.ts	Updates preload API surface to roster get/save, parameterized agent test, and adapter status by agentId.
app/src/main/ipc/project-idea-generator.ts	Uses roster default agent and merges per-agent env into generator invocation.
app/src/main/ipc/chat.ts	Uses roster-selected agent for chat start; uses ACP launch spec per agent and merges per-agent env.
app/src/main/ipc/agents.ts	Adds roster IPC handlers, per-agent launch env/id, ACP launch-spec-by-agent, and ACP handshake test path.
app/src/main/ipc/tests/project-idea-generator.test.ts	Updates mocks and expectations for roster-based agent selection and error copy.
app/src/main/ipc/tests/agent-test.test.ts	Updates tests for new agent:test input shape and adds end-to-end ACP initialize handshake coverage.
app/src/main/ipc/tests/acp-adapter-status.test.ts	Updates adapter-status tests to use roster storage and required agentId.