io.github.j7an/nexus-mcp
Delegate tasks to coding agents (Claude, Codex, Antigravity) from any MCP client
Installation
Ajoutez ceci à la configuration MCP de votre client (Claude Desktop : claude_desktop_config.json ; Cursor : .cursor/mcp.json ; VS Code et les autres utilisent la même forme « mcpServers »).
nexus-mcpclaude mcp add nexus-mcp -- uvx nexus-mcp==2.1.3{
"mcpServers": {
"nexus-mcp": {
"command": "uvx",
"args": [
"nexus-mcp==2.1.3"
]
}
}
}Documentation
Tirée du README du projet sur GitHub, actualisée chaque semaine. Les liens ouvrent GitHub.
Sommaire
nexus-mcp
MCP server that delegates tasks to coding agents — Claude Code via the Claude Agent SDK, Codex via the Codex App Server, and Antigravity via the Antigravity SDK — from any MCP client.
Install
Backends are optional extras; install the ones you use.
| Extra | Backend | Adds |
|---|---|---|
claude | Claude Agent SDK | claude-agent-sdk (bundles the Claude Code CLI, ~100 MB) |
codex | Codex App Server | openai-codex (bundles the Codex CLI, ~120–150 MB) |
antigravity | Antigravity SDK | google-antigravity (bundles the Antigravity Go harness, ~40 MB) |
all | every backend |
uvx --with 'nexus-mcp[all]' nexus-mcp # run directly
pip install 'nexus-mcp[claude]' # or install
pip install 'nexus-mcp[codex]' # Codex only
pip install 'nexus-mcp[antigravity]'Claude Code MCP config:
{ "mcpServers": { "nexus": { "command": "uvx", "args": ["--with", "nexus-mcp[all]", "nexus-mcp"] } } }Authentication is the agent's own: log in with claude, or set ANTHROPIC_API_KEY; for Codex,
log in with codex login (credentials in ~/.codex are shared). Antigravity uses GEMINI_API_KEY,
or Vertex AI with GOOGLE_GENAI_USE_VERTEXAI, GOOGLE_CLOUD_PROJECT, and
GOOGLE_CLOUD_LOCATION, authenticated through Application Default Credentials (ADC). It does not
use Google-account login.
Windows: recent claude-agent-sdk releases ship no Windows wheel with a bundled CLI;
install Claude Code so claude is on PATH.
Tool: prompt
Runs one agent turn and returns its final answer.
| Parameter | Default | Meaning |
|---|---|---|
backend | required | claude, codex, or antigravity |
prompt | required | Task for the agent |
cwd | required | Absolute project directory |
profile | read_only | Permission profile (below) |
session_id | — | Continue this conversation |
fork | false | Branch session_id into a new conversation |
model | provider default | Model id or alias |
timeout | 600 | Seconds before the turn is cancelled |
Returns {backend, session_id, output, usage}. Conversations are stored by the agent itself
(~/.claude/projects, $CODEX_HOME/sessions, ~/.nexus-mcp/antigravity), so a session_id keeps
working after nexus-mcp restarts. Antigravity does not support fork=true.
Permission profiles
Actions outside the chosen profile are denied automatically — nobody is prompted.
| Profile | Allows |
|---|---|
read_only | Read/Glob/Grep; git diff/log/show with --no-ext-diff --no-textconv |
workspace_write | Plus file edits inside cwd and Bash inside the OS sandbox |
full_access | Everything |
Codex enforces profiles with its OS sandbox (read-only, workspace-write, danger-full-access)
and never asks for approval.
Antigravity enforces workspace containment in its harness and uses the OS sandbox for commands.
workspace_write fails if that sandbox is unavailable.
Resource: nexus://backends
JSON list of {name, installed, models, hint}; hint gives the install command for a
missing extra. Codex lists its models; Claude and Antigravity report null (Antigravity does not
provide a model list).
Configuration
| Variable | Default | Meaning |
|---|---|---|
NEXUS_CLAUDE_SETTINGS_PROFILE | isolated | Claude settings to load: isolated (none), project (project .claude/), inherit (all, including user settings). Profiles still bound every tool call. |
Migrating from v1
| v1 | v2 |
|---|---|
prompt(cli="codex") (codex exec) | prompt(backend="codex", cwd=…) (App Server) |
prompt(cli=…, execution_mode="yolo") | prompt(backend=…, profile="full_access", cwd=…) |
batch_prompt | Parallel prompt calls from the client |
agent_start / agent_status / agent_result | prompt (synchronous) |
agent_continue / agent_fork | prompt(session_id=…) / prompt(session_id=…, fork=true) |
agent_review | prompt(profile="read_only", prompt="Review …") |
agent_cancel | Cancel the tool call in the client |
agent_respond, elicitation | Removed — choose a profile instead |
| Preferences, model tiers, MCP prompts | Removed |
| OpenCode runners and tools | Removed |
NEXUS_* variables | Removed except NEXUS_CLAUDE_SETTINGS_PROFILE |
Development
uv sync --all-extras --all-groups
uv run pytest # unit + e2e
uv run pytest -m integration # real CLI (slow, makes model calls)
uv run mypy src/nexus_mcp && uv run ruff check . && uv run ruff format --check .License
MIT
Questions fréquentes
Qu'est-ce que io.github.j7an/nexus-mcp ?
Delegate tasks to coding agents (Claude, Codex, Antigravity) from any MCP client
Comment installer io.github.j7an/nexus-mcp ?
Il s'exécute sur votre machine. Dans Claude Code : claude mcp add nexus-mcp -- uvx nexus-mcp==2.1.3. Pour les autres clients, collez la configuration JSON de cette page dans leurs réglages MCP.
Faut-il une clé API pour io.github.j7an/nexus-mcp ?
Son entrée au registre n'indique aucune clé ni secret obligatoire. Certaines fonctions peuvent tout de même demander un compte auprès du service auquel il se connecte.
io.github.j7an/nexus-mcp est-il open source ?
Oui. Son code est sur GitHub sous licence MIT.
Qui maintient io.github.j7an/nexus-mcp ?
Il est publié par j7an. AI.tn le référence sans le maintenir ni le recommander.
Issu du registre MCP officiel. Être listé n'est pas une recommandation : vérifiez le code et les permissions d'un serveur avant de lui donner accès à vos données.