Installs just this skill. Get the whole plugin for auto-invocation.
⚡ How it fires
How this skill gets triggered: by you, by Claude, or both.
Fires itselfClaude auto-loads it when your prompt matches the work.
You can call itInvoke it directly when you want it.
Slash command/audit-context-building
👁️ Context preview
The summary Claude sees to decide when to auto-load this skill.
Enables ultra-granular, line-by-line code analysis to build deep architectural context before vulnerability or bug finding.
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Stars6,227
Forks540
LanguagePython
LicenseCC-BY-SA-4.0
📦 Ships with trailofbits-skills
</> SKILL.md
audit-context-building.SKILL.md
---name: audit-context-building
description: Enables ultra-granular, line-by-line code analysis to build deep architectural context before vulnerability or bug finding.
---# Deep Context Builder Skill (Ultra-Granular Pure Context Mode)
## 1. Purpose
This skill governs **how Claude thinks** during the context-building phase of an audit.
When active, Claude will:
- Perform **line-by-line / block-by-block** code analysis by default.
- Apply **First Principles**, **5 Whys**, and **5 Hows** at micro scale.
- Continuously link insights → functions → modules → entire system.
- Maintain a stable, explicit mental model that evolves with new evidence.
- Identify invariants, assumptions, flows, and reasoning hazards.
This skill defines a structured analysis format (see Example: Function Micro-Analysis below) and runs **before** the vulnerability-hunting phase.
---## 2. When to Use This Skill
Use when:
- Deep comprehension is needed before bug or vulnerability discovery.
- You want bottom-up understanding instead of high-level guessing.
- Reducing hallucinations, contradictions, and context loss is critical.
- Preparing for security auditing, architecture review, or threat modeling.
Do **not** use for:
Before deep analysis, Claude performs a minimal mapping:
1. Identify major modules/files/contracts.
2. Note obvious public/external entrypoints.
3. Identify likely actors (users, owners, relayers, oracles, other contracts).
4. Identify important storage variables, dicts, state structs, or cells.
5. Build a preliminary structure without assuming behavior.
This establishes anchors for detailed analysis.
---
## 5. Phase 2 — Ultra-Granular Function Analysis (Default Mode)
Every non-trivial function receives full micro analysis.
### 5.1 Per-Function Microstructure Checklist
For each function:
1. **Purpose**
- Why the function exists and its role in the system.
2. **Inputs & Assumptions**
- Parameters and implicit inputs (state, sender, env).
- Preconditions and constraints.
3. **Outputs & Effects**
- Return values.
- State/storage writes.
- Events/messages.
- External interactions.
4. **Block-by-Block / Line-by-Line Analysis**
For each logical block:
- What it does.
- Why it appears here (ordering logic).
- What assumptions it relies on.
- What invariants it establishes or maintains.
- What later logic depends on it.
Apply per-block:
- **First Principles**
- **5 Whys**
- **5 Hows**
---
### 5.2 Cross-Function & External Flow Analysis
*(Full Integration of Jump-Into-External-Code Rule)*
When encountering calls, **continue the same micro-first analysis across boundaries.**
#### Internal Calls
- Jump into the callee immediately.
- Perform block-by-block analysis of relevant code.
- Track flow of data, assumptions, and invariants:
caller → callee → return → caller.
- Note if callee logic behaves differently in this specific call context.
#### External Calls — Two Cases
**Case A — External Call to a Contract Whose Code Exists in the Codebase**
Treat as an internal call:
- Jump into the target contract/function.
- Continue block-by-block micro-analysis.
- Propagate invariants and assumptions seamlessly.
- Consider edge cases based on the *actual* code, not a black-box guess.
**Case B — External Call Without Available Code (True External / Black Box)**
Analyze as adversarial:
- Describe payload/value/gas or parameters sent.
- Identify assumptions about the target.
- Consider all outcomes:
- revert
- incorrect/strange return values
- unexpected state changes
- misbehavior
- reentrancy (if applicable)
#### Continuity Rule
Treat the entire call chain as **one continuous execution flow**.
Never reset context.
All invariants, assumptions, and data dependencies must propagate across calls.
---
### 5.3 Complete Analysis Example
See [FUNCTION_MICRO_ANALYSIS_EXAMPLE.md](resources/FUNCTION_MICRO_ANALYSIS_EXAMPLE.md) for a complete walkthrough demonstrating:
- Full micro-analysis of a DEX swap function
- Application of First Principles, 5 Whys, and 5 Hows
- Block-by-block analysis with invariants and assumptions
- Cross-function dependency mapping
- Risk analysis for external interactions
This example demonstrates the level of depth and structure required for all analyzed functions.
---
### 5.4 Output Requirements
When performing ultra-granular analysis, Claude MUST structure output following the format defined in [OUTPUT_REQUIREMENTS.md](resources/OUTPUT_REQUIREMENTS.md).
