Development
Plugin
harnss
Open-source, desktop client/UI build to harness Claude Code, Codex and any other Agent accepting Agent Client Protocol. Run multiple AI coding agents side by side with rich tool visualization, MCP integrations, built-in terminal, git, browser and just about anything else you may need.
Plugin Signal77/100Solid
maintained100
capable46
documented100
adopted54
Install
$ npx -y skills add OpenSource03/harnss --agent claude-code
Run the curl in your terminal, the rest in Claude Code.
Stats
344
Stars
39
Forks
Active
Maintenance
TypeScript
Language
MIT
License
2h ago
Last commit
5mo ago
Created
Repo: OpenSource03/harnss
What's inside
Agents
7clean-code-refactorUse this agent when you need to refactor existing code, rewrite a module for better maintainability, decompose a large file into focused sub-modules, eliminate duplication, improve type safety, optimize performance, or generally elevate code quality. This agent goes beyond thecode-quality-reviewerUse this agent when you want a comprehensive review of code quality, readability, structure, and maintainability. This agent focuses on how well-written and organized code is — not on bugs, logic errors, or functional correctness. It examines file length, function complexity,docs-researcherUse this agent when the user needs information from project documentation files, SDK docs, protocol specs, or any `@docs` prefixed directories. This includes questions about API usage, SDK methods, protocol details, configuration options, type definitions, or architecturalperf-deep-auditUse this agent when you need a deep performance review of Electron, React, or Vite-related code — especially for large renders, long chat histories, streaming updates, memory leaks, IPC bottleneck analysis, or general app sluggishness investigations. This agent reviews andrefactor-analystUse this agent when you need a thorough code quality analysis and refactoring recommendations for specific files, directories, or an entire branch. This agent reads code deeply, questions every pattern, checks for modern best practices, and produces a detailed report — withoutrefactor-validatorUse this agent when a significant refactoring has been completed and you need to verify that the changes are correct, consistent, and haven't introduced regressions. This includes verifying type safety, import consistency, runtime behavior preservation, and adherence to project
README
1[!CAUTION] Harnss is currently pending a large rewrite to improve usability, performance and overall codebase into a more production ready app. I will share more info about it soon.
[!WARNING] Harnss is in early development and issues are to be expected. Please feel free to report bugs and issues in the Issues section.
Harnss is a cross-platform desktop app that gives you one interface to run, manage, and switch between AI coding agents — Claude Code, Codex, and any ACP-compatible agent — without losing context, sessions, or tool state.
Why Harnss?
- One app, every agent. Run Claude Code, Codex, and custom ACP agents side by side. No more juggling terminals or losing context when switching tools.
- See what your AI is actually doing. Tool calls render as interactive cards with word-level diffs, syntax highlighting, and inline bash output — not raw JSON.
- Your workspace, your way. Built-in terminal, browser, git, MCP servers, and file panels — all scoped per project, all staying open while you work.
Screenshots
https://github.com/user-attachments/assets/41f5bcbc-c141-4a16-b430-79f8e01d107e
Features
Multi-engine sessions
Run Claude Code (via the Anthropic SDK), Codex, and ACP-compatible agents in parallel. Each session has its own state, history, and context. Switch between them instantly.
Rich tool visualization
Every tool call renders as an interactive card. File edits show word-level diffs with syntax highlighting. Bash output appears inline. Subagent tasks nest with step-by-step progress tracking. File changes are summarized per turn with a dedicated Changes panel.
MCP server management
Connect any MCP server per project via stdio, SSE, or HTTP transport. OAuth flows are handled automatically. Server status and available tool counts are visible at a glance. Jira, Confluence, and other integrations render with dedicated UIs rather than raw JSON.
Git integration
Stage, unstage, commit, and push without leaving the app. Browse branches, view commit history, and manage git worktrees. AI-generated commit messages are available from the staged diff.
Built-in terminal & browser
Multi-tab PTY terminal backed by native shell processes. An embedded browser for opening URLs inline and providing additional context to the agent. Both panels stay mounted while you work.
Project workspaces & spaces
Projects map to folders on disk. Spaces let you organize projects into named groups with custom icons and colors. Sessions, history, and panel settings are all scoped per project.
Agent Store
Browse and install agents from the ACP community registry directly in the app. Add custom agents by specifying a command, arguments, environment variables, and an icon. All configuration is managed through Settings — no config files.
Plan mode & permission control
Work in plan mode to have the agent draft a plan before making any changes. Three permission levels — Ask First, Accept Edits, Allow All — control how much autonomy the agent has. Switch modes at any point without interrupting context.
Background task agents
Task agents spawned during a session continue running in the background and are tracked in a dedicated panel. Keep working in other sessions while long-running tasks complete.
Image attachments & annotation
Attach screenshots or images directly in the chat. An built-in annotation tool lets you draw, highlight, and mark up images with freehand strokes before sending them to the agent.
Voice input & notifications
Voice input via native macOS dictation or an on-device Whisper model (no API key required). Configurable OS notifications for plan approval requests, permission prompts, agent questions, and session completion.
Session search & history
Full-text search across session titles and message content. Import and resume conversations previously started in the Claude Code CLI.
Quick Start
- Download the latest release for your platform from the Releases page
- Open a project — point Harnss at any folder on disk
- Choose an engine — Claude Code, Codex, or any installed ACP agent — and start working
Engines & Agents
Harnss supports three execution engines out of the box:
| Engine | Protocol | Requirements |
|---|---|---|
| Claude Code | Anthropic Agent SDK | Claude account (subscription or API key) |
| Codex | JSON-RPC app-server | Codex CLI in PATH + OpenAI API key or ChatGPT account |
| ACP agents | Agent Client Protocol | Agent-specific (see registry) |
Claude Code and Codex are built-in. ACP agents can be installed from the ACP Agent Registry inside the app, or configured manually.
Examples of installable ACP-compatible agents:
| Agent | Command | Notes |
|---|---|---|
| Gemini CLI | gemini --experimental-acp | Experimental ACP flag |
| Goose | goose acp | |
| Docker cagent | cagent acp agent.yml | Container-based agents |
Adding an agent
Open Settings → ACP Agents. The Agent Store tab lets you browse and install agents from the community registry. The My Agents tab lets you create custom agents — set the binary command, arguments, environment variables, and icon, or paste a JSON definition to auto-fill the form.
MCP Servers
MCP servers are configured per project through the MCP Servers panel in the right-side toolbar. Supported transports: stdio, SSE, and HTTP. OAuth authentication is handled in-app with token persistence across sessions.
Install
[!NOTE] Pre-built binaries are currently unsigned. On macOS, right-click the app and choose Open to bypass the Gatekeeper warning on first launch. On Windows, click More info → Run anyway if Windows Defender flags the installer.
| Platform | Download |
|---|---|
| macOS (Apple Silicon) | .dmg (arm64) |
| macOS (Intel) | .dmg (x64) |
| Windows (x64) | .exe installer |
| Windows (ARM64) | .exe installer |
| Linux | .AppImage / .deb |
Development
git clone https://github.com/OpenSource03/harnss.git
cd harnss
pnpm install
pnpm dev
Build installers
pnpm dist:mac # macOS DMG (arm64 + x64)
pnpm dist:win # Windows NSIS installer (x64 + ARM64)
pnpm dist:linux # Linux AppImage + deb
Contributing
- Fork the repo and create a feature branch
- Follow the conventions in
CLAUDE.md - Test with
pnpm dev - Open a pull request
License
MIT
File tree
1047OpenSource03/harnssView on GitHub
.agents/
skills/
release/
references/
release-notes-template.md
SKILL.md
vercel-react-best-practices/
AGENTS.md
README.md
rules/
_sections.md
_template.md
advanced-event-handler-refs.md
advanced-init-once.md
advanced-use-latest.md
async-api-routes.md
async-defer-await.md
async-dependencies.md
async-parallel.md
async-suspense-boundaries.md
bundle-barrel-imports.md
bundle-conditional.md
bundle-defer-third-party.md
bundle-dynamic-imports.md
bundle-preload.md
client-event-listeners.md
client-localstorage-schema.md
client-passive-event-listeners.md
client-swr-dedup.md
js-batch-dom-css.md
js-cache-function-results.md
js-cache-property-access.md
js-cache-storage.md
js-combine-iterations.md
js-early-exit.md
js-flatmap-filter.md
js-hoist-regexp.md
js-index-maps.md
js-length-check-first.md
js-min-max-loop.md
js-set-map-lookups.md
js-tosorted-immutable.md
rendering-activity.md
rendering-animate-svg-wrapper.md
rendering-conditional-render.md
rendering-content-visibility.md
rendering-hoist-jsx.md
rendering-hydration-no-flicker.md
rendering-hydration-suppress-warning.md
rendering-resource-hints.md
rendering-script-defer-async.md
rendering-svg-precision.md
rendering-usetransition-loading.md
rerender-defer-reads.md
rerender-dependencies.md
rerender-derived-state-no-effect.md
rerender-derived-state.md
rerender-functional-setstate.md
rerender-lazy-state-init.md
rerender-memo-with-default-value.md
rerender-memo.md
rerender-move-effect-to-event.md
rerender-no-inline-components.md
rerender-simple-expression-in-memo.md
rerender-transitions.md
rerender-use-ref-transient-values.md
server-after-nonblocking.md
server-auth-actions.md
server-cache-lru.md
server-cache-react.md
server-dedup-props.md
server-hoist-static-io.md
server-parallel-fetching.md
server-serialization.md
SKILL.md
.claude/
agents/
clean-code-refactor.md
code-quality-reviewer.md
docs-researcher.md
perf-deep-audit.md
refactor-analyst.md
refactor-validator.md
typescript-type-reviewer.md
skills/
release/
references/
release-notes-template.md
SKILL.md
vercel-react-best-practices
.github/
banner.png
CODEOWNERS
FUNDING.yml
ISSUE_TEMPLATE/
bug_report.yml
config.yml
feature_request.yml
pull_request_template.md
workflows/
build.yml
.gitignore
.harnss/
worktree.json
.npmrc
AGENTS.md
build/
entitlements.mac.plist
icon.icns
icon.ico
icon.icon/
Assets/
harnss-light 2.png
harnss.pngdark.png
icon.json
icon.png
icons/
1024x1024.png
128x128.png
16x16.png
24x24.png
256x256.png
32x32.png
48x48.png
512x512.png
64x64.png
CLAUDE.md
components.json
electron/
electron-builder.config.js
src/
ipc/
acp-sessions.ts
agent-registry.ts
cc-import.ts
claude-sessions.ts
codex-sessions.ts
files.ts
folders.ts
git.ts
jira.ts
mcp.ts
projects.ts
sessions.ts
settings.ts
spaces.ts
terminal.ts
title-gen.ts
lib/
__tests__/
acp-auth.test.ts
chat-scroll.test.ts
claude-binary.test.ts
layout-constants.test.ts
logger.test.ts
notification-utils.test.ts
sdk.test.ts
session-derived-data.test.ts
terminal-history.test.ts
terminal-tabs.test.ts
updater.test.ts
acp-auth.ts
acp-utility-prompt.ts
agent-registry.ts
app-settings.ts
async-channel.ts
claude-binary.ts
claude-model-cache.ts
codex-binary.ts
codex-rpc.ts
codex-utility-prompt.ts
data-dir.ts
error-utils.ts
git-exec.ts
glass.ts
jira-client.ts
jira-oauth-store.ts
jira-store.ts
json-file-store.ts
logger.ts
mcp-oauth-flow.ts
mcp-oauth-provider.ts
mcp-oauth-store.ts
mcp-store.ts
migration.ts
posthog.ts
prerelease-check.ts
safe-send.ts
sdk.ts
terminal-history.ts
updater.ts
main.ts
preload.ts
tsconfig.json
index.html
LICENSE
package.json
pnpm-lock.yaml
pnpm-workspace.yaml
public/
icon.png
sounds/
notification.wav
README.md
scripts/
delay.js
notarize.js
test-update-local.sh
shared/
lib/
acp-helpers.ts
async-channel.ts
codex-helpers.ts
codex-rpc.ts
error-utils.ts
mcp-config.ts
session-persistence.ts
types/
acp.ts
codex-protocol/
AbsolutePathBuf.ts
AddConversationListenerParams.ts
AddConversationSubscriptionResponse.ts
AgentMessageContent.ts
AgentMessageContentDeltaEvent.ts
AgentMessageDeltaEvent.ts
AgentMessageEvent.ts
AgentMessageItem.ts
AgentReasoningDeltaEvent.ts
AgentReasoningEvent.ts
AgentReasoningRawContentDeltaEvent.ts
AgentReasoningRawContentEvent.ts
AgentReasoningSectionBreakEvent.ts
AgentStatus.ts
ApplyPatchApprovalParams.ts
ApplyPatchApprovalRequestEvent.ts
ApplyPatchApprovalResponse.ts
ArchiveConversationParams.ts
ArchiveConversationResponse.ts
AskForApproval.ts
AuthMode.ts
AuthStatusChangeNotification.ts
BackgroundEventEvent.ts
ByteRange.ts
CallToolResult.ts
CancelLoginChatGptParams.ts
CancelLoginChatGptResponse.ts
ClientInfo.ts
ClientNotification.ts
ClientRequest.ts
CodexErrorInfo.ts
CollabAgentInteractionBeginEvent.ts
CollabAgentInteractionEndEvent.ts
CollabAgentRef.ts
CollabAgentSpawnBeginEvent.ts
CollabAgentSpawnEndEvent.ts
CollabAgentStatusEntry.ts
CollabCloseBeginEvent.ts
CollabCloseEndEvent.ts
CollaborationMode.ts
CollaborationModeMask.ts
CollabResumeBeginEvent.ts
CollabResumeEndEvent.ts
CollabWaitingBeginEvent.ts
CollabWaitingEndEvent.ts
ContentItem.ts
ContextCompactedEvent.ts
ContextCompactionItem.ts
ConversationGitInfo.ts
ConversationSummary.ts
CreditsSnapshot.ts
CustomPrompt.ts
DeprecationNoticeEvent.ts
DynamicToolCallRequest.ts
ElicitationRequestEvent.ts
ErrorEvent.ts
EventMsg.ts
ExecApprovalRequestEvent.ts
ExecCommandApprovalParams.ts
ExecCommandApprovalResponse.ts
ExecCommandBeginEvent.ts
ExecCommandEndEvent.ts
ExecCommandOutputDeltaEvent.ts
ExecCommandSource.ts
ExecCommandStatus.ts
ExecOneOffCommandParams.ts
ExecOneOffCommandResponse.ts
ExecOutputStream.ts
ExecPolicyAmendment.ts
ExitedReviewModeEvent.ts
FileChange.ts
FileSystemPermissions.ts
ForcedLoginMethod.ts
ForkConversationParams.ts
ForkConversationResponse.ts
FunctionCallOutputBody.ts
FunctionCallOutputContentItem.ts
FunctionCallOutputPayload.ts
FuzzyFileSearchParams.ts
FuzzyFileSearchResponse.ts
FuzzyFileSearchResult.ts
FuzzyFileSearchSessionCompletedNotification.ts
FuzzyFileSearchSessionUpdatedNotification.ts
GetAuthStatusParams.ts
GetAuthStatusResponse.ts
GetConversationSummaryParams.ts
GetConversationSummaryResponse.ts
GetHistoryEntryResponseEvent.ts
GetUserAgentResponse.ts
GetUserSavedConfigResponse.ts
GhostCommit.ts
GitDiffToRemoteParams.ts
GitDiffToRemoteResponse.ts
GitSha.ts
HistoryEntry.ts
index.ts
InitializeCapabilities.ts
InitializeParams.ts
InitializeResponse.ts
InputItem.ts
InputModality.ts
InterruptConversationParams.ts
InterruptConversationResponse.ts
ItemCompletedEvent.ts
ItemStartedEvent.ts
ListConversationsParams.ts
ListConversationsResponse.ts
ListCustomPromptsResponseEvent.ts
ListRemoteSkillsResponseEvent.ts
ListSkillsResponseEvent.ts
LocalShellAction.ts
LocalShellExecAction.ts
LocalShellStatus.ts
LoginApiKeyParams.ts
LoginApiKeyResponse.ts
LoginChatGptCompleteNotification.ts
LoginChatGptResponse.ts
LogoutChatGptResponse.ts
MacOsAutomationValue.ts
MacOsPermissions.ts
MacOsPreferencesValue.ts
McpAuthStatus.ts
McpInvocation.ts
McpListToolsResponseEvent.ts
McpStartupCompleteEvent.ts
McpStartupFailure.ts
McpStartupStatus.ts
McpStartupUpdateEvent.ts
McpToolCallBeginEvent.ts
McpToolCallEndEvent.ts
MessagePhase.ts
ModeKind.ts
ModelRerouteEvent.ts
ModelRerouteReason.ts
NetworkAccess.ts
NetworkApprovalContext.ts
NetworkApprovalProtocol.ts
NetworkPolicyAmendment.ts
NetworkPolicyRuleAction.ts
NewConversationParams.ts
NewConversationResponse.ts
ParsedCommand.ts
PatchApplyBeginEvent.ts
PatchApplyEndEvent.ts
PatchApplyStatus.ts
PermissionProfile.ts
Personality.ts
PlanDeltaEvent.ts
PlanItem.ts
PlanItemArg.ts
PlanType.ts
Profile.ts
RateLimitSnapshot.ts
RateLimitWindow.ts
RawResponseItemEvent.ts
ReadOnlyAccess.ts
RealtimeAudioFrame.ts
RealtimeConversationClosedEvent.ts
RealtimeConversationRealtimeEvent.ts
RealtimeConversationStartedEvent.ts
RealtimeEvent.ts
ReasoningContentDeltaEvent.ts
ReasoningEffort.ts
ReasoningItem.ts
ReasoningItemContent.ts
ReasoningItemReasoningSummary.ts
ReasoningRawContentDeltaEvent.ts
ReasoningSummary.ts
RejectConfig.ts
RemoteSkillDownloadedEvent.ts
RemoteSkillSummary.ts
RemoveConversationListenerParams.ts
RemoveConversationSubscriptionResponse.ts
RequestId.ts
RequestUserInputEvent.ts
RequestUserInputQuestion.ts
RequestUserInputQuestionOption.ts
Resource.ts
ResourceTemplate.ts
ResponseItem.ts
... 713 moreFAQ
harnss is a Claude Code plugin with 1 hand-picked skill for development work, indexed on Flowy. Install it with the command on its page. It includes release. Its skills do not fire on their own yet. Request auto-invocation to have Flowy route them as you prompt. Free and open source.
- What is harnss?
- Open-source, desktop client/UI build to harness Claude Code, Codex and any other Agent accepting Agent Client Protocol. Run multiple AI coding agents side by side with rich tool visualization, MCP integrations, built-in terminal, git, browser and just about anything else you may need.
- How do I install harnss?
- Run these in Claude Code: npx -y skills add OpenSource03/harnss --agent claude-code. Then prompt normally.
- Does harnss auto-invoke its skills?
- Not yet. It is indexed on Flowy as a plain plugin. Request auto-invocation on its page and Flowy will route its skills for you as you prompt.
- Is harnss free?
- Yes. Flowy is free and open source, with nothing gated. You can read every skill in full before you install.