Claude Code

The decide plugin gives Claude a second opinion. Once it’s installed, it works in the background, and it adds two skills you run yourself: one audits a repository for security bugs, and one finds where a fixed bug was repeated. This guide shows how to set it up and use each part. For what each check asks, what it sends, and its options, see the plugin’s README.

In three steps

You need Claude Code 2.1.287 or later, decide 0.4.0 or later, and a key for a decision model.

1. Install decide and set your key:

   brew install deepnoodle-ai/tap/decide
   export TYPESAFE_API_KEY=...

   To use Workers AI or OpenAI instead, set that provider’s variables, as Providers shows. Set them where Claude Code will see them, such as in your shell profile. Check that decide works:

   echo "I love it" | decide run sentiment

2. In Claude Code, add the marketplace and install the plugin:

   /plugin marketplace add deepnoodle-ai/decide
   /plugin install decide@decide

3. Restart Claude Code. If it can’t find decide, such as when you start it from an app rather than a terminal, set decidePath in /plugin to the full path from which decide.

To update later, run brew upgrade decide, then update the plugin:

claude plugin update decide@decide

Then restart Claude Code. To update on its own, turn on auto-update for the marketplace in /plugin. The plugin needs the decide release with the same version number or a later one.

What happens on its own

You don’t need to do anything for these:

• Content from outside is checked. After Claude reads a web page, search results, an MCP tool’s result, or gh, curl, wget, or http output, decide checks whether it tries to take over an AI agent or hide text from you. If it does, Claude reads a warning beside the result, and you see a toast.
• Severe commands are checked, in bypass mode only. Before each shell command runs, decide checks whether it could do severe harm that’s hard to undo, such as deleting a home folder or force-pushing a shared branch. If so, you choose whether it runs. Set commands to deny or off in /plugin to change this.
• Claude can ask its own questions. The judge tool, mcp__decide__judge, lets Claude ask typed questions about up to 200 items, such as which of these issues are bugs.

The footer shows a count, such as decide 12 checked, 1 flagged, and /decide shows the session’s checks in a table. A ⚠ in the status line means some actions went unchecked or a check is off; /decide says why.

Audit for security bugs

Run /decide:audit from the repository you want to review:

/decide:audit
/decide:audit internal/api cmd/server

Name paths to audit only part of the repository. Claude then:

1. Picks the server code, leaving out tests, generated and vendored code, and examples, and counts the functions. Over 5,000 functions, it asks you before going on.
2. Runs decide’s security template on every function. In one request per function, it asks about SQL and command injection, SSRF, XSS, weak ciphers, hashes and random values, and TLS checks turned off.
3. Takes up to 15 of the highest-scoring functions, those with an answer of 30% or more, and reads each one, with its callers, in parallel. If none scores that high, it says so and stops.
4. Reports a table of findings, each confirmed or suspected, with the reason, and counts the ones it dismissed.

decide’s scores show where to look; they don’t prove a bug. A finding is confirmed only after Claude reads the code. When it’s done, ask Claude to write a failing test for each finding, or to fix them. If more functions scored 30% or more, ask it to read the next 15, which costs no new requests.

The audit doesn’t cover path traversal, authorization, or deserialization, and it can miss a bug that spans several functions.

Find the rest of a fixed bug

When you fix a bug, the same mistake is often somewhere else. Give /decide:hunt the fix, as a commit or a pull request:

/decide:hunt 87
/decide:hunt a1b2c3d
/decide:hunt

With no argument, it uses the last commit. Claude then:

1. Reads the fix and picks the one mistake most likely to be repeated.
2. Writes one yes-or-no question about that mistake.
3. Tests the question: it must flag the code before the fix and pass the code after it. If it doesn’t, Claude rewrites it.
4. Asks the question of every function, and reads up to ten of the highest, those that score 30% or more.
5. Reports which are the same bug and which aren’t.

The question is saved as a template, such as .decide/templates/bug-87, and Claude offers to commit it. Committed, it can check later changes for the same bug, such as in CI:

git diff main | decide run bug-87 --each function --fail-on matched

Use the results outside Claude

Each audit and hunt is a saved decide run. To read one again in your terminal:

decide runs                        # list runs
decide runs view <run-id> --top 15 # flagged first, then nearest a flag

Answers are cached, so running an audit again asks only about functions that changed. The background checks are saved separately:

DECIDE_HOME=~/.decide/agent decide runs

What it sends

Each check sends the text it checks to the decision model’s provider, with your key: in bypass mode, each shell command; each outside result the content check reads; and with an audit or a hunt, every function it covers. Runs and answers stay in ~/.decide on your disk. See What it sends and keeps.