Blast Radius

See what any MCP server can actually touch — before you add it to your agent.

No manifest? You still get the full blast-radius report. Add a manifest to also catch divergences.

Also, if the server declares a manifest: Catch an MCP server that touches files it said it wouldn't — and block the merge in CI.

Statically extract what a third-party MCP server can reach (files, network, subprocess, env) via surface-level analysis. Compare against declared boundaries when a manifest is present.

Try it in 3 steps

1 — Install & scan

pip install mcp-blast-radius==0.2.2
mcp-blast-radius-gate --gate-mode advisory --target-dir /path/to/mcp-server

2 — Example target (any cloned MCP repo root)

git clone --depth 1 https://github.com/oraios/serena.git /tmp/serena
mcp-blast-radius-gate --gate-mode advisory --target-dir /tmp/serena

3 — Report findings — Open a GitHub issue with your JSON output (structured template loads automatically).

30-second scan

pip install mcp-blast-radius
mcp-blast-radius-gate --gate-mode blocking --target-dir /path/to/mcp-server

pipx run mcp-blast-radius starts the MCP stdio server (for Claude Desktop / Cursor). For CLI scanning, use mcp-blast-radius-gate as above.

• Red (blocking): divergence detected — code touches paths or capabilities not declared in manifest.
• Green: no divergences (or no manifest — blast radius report only, advisory pass).

Install

python3 -m venv .venv
source .venv/bin/activate
pip install .

CLI entry

mcp-blast-radius          # MCP stdio server
mcp-blast-radius-gate     # CI gate (default blocking, exit 1 on fail)

CI blocking gate

mcp-blast-radius-gate --gate-mode blocking --target-dir .
# no divergences → exit 0 / divergences or declaration violations → exit 1

MCP tools

• aos_compliance_validate — scan one MCP server directory (target_dir required; tool_id optional label)
• aos_compliance_self_test — wiring smoke test

Default gate_mode=advisory. Use gate_mode=blocking in CI to fail on divergences.

What is extracted

Layer	Scope	Confidence
Dependencies	requirements.txt, pyproject.toml, package.json	declared
Python AST	imports, file I/O, network, env, subprocess; MCP tool attribution	observed-static / cannot-determine
Divergence	manifest permitted_output_paths / oracle_paths vs observed access	blocking when mismatch

Limitations: Static analysis only. Dynamic imports, getattr/eval, obfuscation, and native extensions may hide capabilities. We do not claim complete coverage — every finding includes a confidence label.

Environment

Variable	Purpose
AOS_VALIDATOR_TARGET_DIR	Default scan root when target_dir is omitted
AOS_VALIDATOR_MCP_LOG	JSONL path for local tool call log (never sent externally)
AOS_VALIDATOR_CALLER	Caller label (ci, smoke_self_call, etc.)

Example

aos_compliance_validate target_dir=/path/to/my-mcp-server gate_mode=blocking

License

MIT