kiff-scan

What can your AI agent do without asking?

kiff-scan finds Python functions that are callable by a model and reach an action that deletes data, deploys, moves money, rotates a credential, or runs a shell, with nothing on the path that can refuse.

uvx kiff-scan scan .

No install, no account, no config. Zero dependencies, no network code, and it never executes the code it reads. All three are CI tests, not claims.

Need to show what is governed, what is not, and why? Generate an evidence-backed assessment for an engineering or governance review:

uvx kiff-scan evidence . --format html --output kiff-report.html

The assessment turns the same source evidence into a readiness result, hard blockers, a six-dimension governability scorecard, an action register, and a prioritized remediation plan. Missing evidence is marked not evidenced or not assessable; it is never converted into a pass. See Agent governability assessment.

Output

Run against awslabs/mcp's IAM server at e9f2439:

kiff-scan · what can this agent do without a decision?

  YOUR AGENT'S BLAST RADIUS

  Consequential capabilities: 6
    Decision found on path:   0
    Review required:          6

    Secrets / identity    6   add_user_to_group, attach_user_policy, create_access_key,
                              delete_access_key, delete_user, put_user_policy

  Most exposed: awslabs/iam_mcp_server/server.py:431  delete_user()
    Reachable by:            @tool
    Consequence:             Secrets / identity  (calls delete_access_key())
    Severity:                high
    Match confidence:        call
    Decision on path:        none found on the analysed path
    Model-controlled inputs: user_name, force, confirmed

    State-dependent: an authorization check is necessary but NOT
    sufficient here.

Six tools, six IAM mutations, no decision between the model's argument and the SDK call. Every one is a real @mcp.tool in that repository.

Why an auth check is not enough

Seven of the eight consequence categories are marked state-dependent. A rollback to a broken revision, a failover to a region you already failed over to, a DROP against the live database instead of the drained replica, a refund issued twice before the first settles: each passes every role check you can write, and each is wrong because of when it ran, not who asked.

For those, "add an authorization check" is the wrong fix. The scanner says so instead of implying the check would have been enough.

Accuracy

Ten public repositories, pinned at exact commits, findings labelled by hand:

python bench/run.py

Recall is 0.65 because six labelled findings are not reached. All six are the same gap: the destructive call lives in another module. The benchmark includes four repositories where that gap is known to bite, so the number can go down as well as up.

Read the precision honestly. Eleven scored findings is a small set, and four of the ten repositories correctly report nothing, which does not test precision at all. Labels are in bench/expected/, each naming the call that justifies it.

Against the previous release on identical trees:

What it will not flag

Each has a regression test:

• agent.run(), chain.run(), client.call(). Execution needs an execution receiver (subprocess, os, asyncio, pexpect, pty) or shell=True.
• Console().capture(). That is rich's output buffer, not a payment capture.
• select_dropdown(). Names match on whole tokens, so drop is a token of drop_database and is not a token of dropdown.
• get_*, list_*, check_* when the finding comes from the name alone. An observed delete_table() in the body still reports.
• @app.task in a repo that imports no agent framework. That is a Celery job.
• subprocess.run(["say", text]) reports at low, not high. A fixed program with model-controlled arguments is not a shell.
• Findings under tests/, examples/, cookbook/, docs/ are listed but not counted. Pass --include-tests to count them.

What it reads from your framework

A tool that declares requires_confirmation=True (agno), needs_approval=True (OpenAI Agents SDK), external_execution=True, or MCP ToolAnnotations(readOnlyHint=True) is treated as governed. Your framework already gates it.

The reverse is a finding of its own:

  ANNOTATION MISMATCH (1)

    warehouse.py:14  inspect_table()
      declares:  readOnlyHint=True
      but:       calls delete_table()

The tool's own metadata is the accuser.

Your code does not leave your machine

These run on every push, every pull request, and daily. Reports contain file paths, line numbers, and parameter names from signatures, never argument values or source text. A test enforces that too.

Detail in docs/THREAT_MODEL.md.

Install

uvx kiff-scan scan .          # no install
uvx kiff-scan evidence .        # management-ready Markdown evidence report
pipx install kiff-scan        # or
pip install kiff-scan

Python 3.10+. In CI:

- uses: kiff/kiff-scan@v0.3.0
  with:
    path: .
    fail-on: high

Limits

• Python only. Other languages are reported as unsupported, never counted as clean.
• Calls are followed within a module, up to four hops. A destructive call one import away is missed. This is the largest source of false negatives.
• Lexical precedence, not control flow. A guard inside if not force: is credited even though a caller can skip it.
• Guards are recognised by name. An authorize() that always returns True clears a finding.
• Agent(tools=[fn]) list registration and JSON-schema dispatch tables are not resolved.

A clean scan means no supported path was found. It is not evidence the code is safe. Full list in docs/COVERAGE.md.

Help build the data

The benchmark is a starting point, not a result. Ten repositories and eleven scored findings is enough to catch a regression and not enough to characterise how this behaves across the ecosystem.

Useful contributions, in rough order of value:

1. A repository where it is wrong. A missed sink, a false positive, a guard it should have honoured, or a clean result on code that is not. Open an issue with the repo, the commit, and the function. Accepted cases become fixtures.
2. A framework it does not understand. If your tools are registered in a shape that is not in docs/COVERAGE.md, that is a gap worth a fixture even before it is fixed.
3. A labelled repository for bench/. Add an entry to bench/repos.json with a pinned commit and a bench/expected/<name>.json where every label says which call justifies it. Repositories where the scanner does badly are more useful than ones where it does well.
4. Numbers from your own codebase. Findings before and after, how many you agreed with, what it missed. Aggregate counts are useful even without the source.

Known misses stay on the list before they are fixed. A challenge list showing only fixed cases is a trophy cabinet.

Docs

• User guide. Reading a report, explain, CI, config, suppressions, exit codes.
• Assessment. Readiness rules, evidence states, report formats, and claim boundaries.
• Coverage. Every registration shape and sink, supported and not.
• Threat model.

Where this comes from

I build KIFF, a runtime for the decision this scanner asks for. The scanner does not need it, does not talk to it, and works the same without it. Guard detection is vendor-neutral: your own authorize() clears a finding exactly as anything else does.

License

MIT.