Install Audit Context Building
Pick your agent. Every command is ready to paste.
npx skills add trailofbits/skills --skill audit-context-buildingThe open skills CLI detects your agents (Claude Code, Cursor, Codex and 70+ more) and installs to the right folder. Add -g to install globally.
01
Install it
Run the command above, or upload the folder in Claude.
02
Ask naturally
Describe the task. Your agent loads audit-context-building when the request matches its description.
03
Name it if needed
If it does not trigger, say “use the audit-context-building skill”. In Codex, type $audit-context-building.
Audit Context Building
Build understanding, not verdicts. This runs before anyone hunts for bugs, and feeds that work.
When to Use
At the start of an audit, a threat model, or an architecture review, when the code is unfamiliar. Also when an earlier pass produced findings nobody could judge, because no one had mapped out how the system fits together.
When NOT to Use
Do not name vulnerabilities, suggest fixes, write proofs-of-concept, or rate severity. Those belong to the hunting phase, which runs next and with the whole picture in hand. When the code counts on something and nothing checks it, record that plainly and move on — whether it matters is decided later.
Not worth the tokens on code you already understand.
Do not analyze in this context
The analysis is long, and this context needs to survive to use it. Dispatch it:
- A codebase, or more than one function — run
/audit-context-building:audit-context <path>. It orients, analyzes each function in its own subagent, and writesaudit-context/DOSSIER.mdplus one file per function underaudit-context/functions/. Only compact records return here. - A single function — dispatch the
audit-context-building:function-analyzeragent at it. It writes its prose to disk and returns a record.
Then work from what comes back: the index, the unenforced assumptions, the open questions. Read a function's file when you need its detail.
The workflow is what enforces this, not this text: a subagent bound to a return schema cannot return prose. Treat this section as routing, and route.
What comes back, and how to read it
Each record lists what must always be true (with the line that shows it), what the function takes on faith (with whatever establishes it), which functions it calls and what it needs from each, and anything still unclear. The dossier adds the rules that span several functions, who can reach what, and where the complicated parts cluster.
Two things matter more than the rest:
- Assumptions marked
nothing found. The code counts on something being true and nothing anywhere makes it true. This is the most useful thing to hand the hunting phase. - The open questions. An honest list of what is still unclear beats a confident answer that turns out to be wrong. Carry them forward instead of closing them out.
Where two records disagree, both are quoted rather than quietly reconciled. That is a fact about the code, not a flaw in the analysis.
The format
ANALYSIS_FORMAT.md defines it, and FUNCTION_MICRO_ANALYSIS_EXAMPLE.md works through examples in C and Solidity. Read them when extending this plugin or deciding whether a record can be trusted.
The format is the same whatever the target. What changes is what fills each slot, and what counts as a call you cannot see inside. DOMAIN_NOTES.md maps that across smart contracts, C and C++, decompiled firmware, and web services — read it when the target is not plain source code.
The rule that matters most: follow the calls. Whether a function is correct usually depends on something
another function does, and you cannot see that from the caller alone. A limit looks enforced because the
value came back from a function whose name suggests it was checked. So read the function being called, follow
every path through it rather than only the one that succeeds, and say what makes each assumption true. When
nothing does, use those words: nothing found. Every claim cites a line, or becomes an open question.
Tips for Audit Context Building
- • Start a fresh session after installing so your agent picks up the new skill.
- • It bundles reference files. The agent reads them only when needed, so they cost no context until then.
- • It is part of a pack with 30 skills. Install only the ones you need with --skill to keep triggers precise.
- • If two skills overlap, mention the one you want by name.
Questions about Audit Context Building
What does the Audit Context Building skill do?
Understand a codebase before looking for bugs in it - what each function assumes, what it guarantees, and what it depends on elsewhere. Use when starting an audit, threat model, or architecture review on unfamiliar code, and before any vulnerability-hunting pass.
How do I install Audit Context Building?
Run "npx skills add trailofbits/skills --skill audit-context-building" in your project. The skills CLI installs it for Claude Code, Cursor, Codex and 70+ other agents. In Claude on the web, upload the skill folder as a ZIP under Customize > Skills.
Does Audit Context Building work in Cursor and Codex?
Yes. Audit Context Building uses the open SKILL.md format, so it works in Claude Code, Claude, Cursor, OpenAI Codex, Gemini CLI, GitHub Copilot and other agents that support agent skills.
Is Audit Context Building free?
Audit Context Building is open source on GitHub under the CC-BY-SA-4.0 license. It is free to install; check the license before commercial use.
Who made Audit Context Building?
Audit Context Building is published by trailofbits in the trailofbits/skills repository, together with 29 other skills.





