Nexus Mcp — independently scanned and version-tracked by SaferSkills.
SaferSkills independently audited Nexus Mcp (Agent Skill) and scored it 100/100 (green). The audit ran 55 deterministic rules across Security, Supply Chain, Maintenance, Transparency, and Community; it found 0 high-severity and 0 lower-severity findings. The full rule-by-rule trace and per-finding evidence are below. Free, methodology-open.
Findings & checks · 0 flagged
Every scanned point with the score it earned and what moved between them.
First recorded scan — no prior version to compare against.
The primary manifest — the file an agent reads to learn what this artifact does.
<!-- mcp-name: io.github.j7an/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.
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.
promptRuns 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.
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.
nexus://backendsJSON 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).
| 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. |
| 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 |
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 .MIT
~30 seconds. Free. No account. Every finding cites a rule and a line of evidence.