Prior Art & Reference Patterns Skill

Search → Audit → Adapt → Clean

This skill is the procedure the ambient Outward-Search Reflex invokes (ambient.md §"Outward-Search Reflex"). The mandate is ambient — every walker that reaches a design fork, a missing fact, or a non-trivial pattern runs this procedure before halting. The skill documents the how: tiered search, shallow-clone workspace hygiene, ≥2-reference grounding, and cleanup before every commit.

Adversarial path anchor. This lens is also invoked on the Verification Dual's adversarial path (rules.md §2 Invariant 1): the Dual's thesis — externalize correctness, never trust the generator's confidence — applies to external knowledge. Internal confidence is not evidence; a context-free search in decorrelated sources (production code, RFCs, literature) closes the condition where no deterministic evaluator exists.

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1. Search Hierarchy Directive

When addressing a non-trivial architectural or algorithmic task, you must systematically search for existing work using the following priority tiers:

graph TD
    A["Start Search Walk"] --> B{"Tier 1: Production Code Available & Permissive?"}
    B -- "Yes" --> C["Audit Code & Extract Invariants (MIT/Apache-2.0)"]
    B -- "No / Restricted (GPL)" --> D{"Tier 2: Official Standards / RFCs Available?"}
    D -- "Yes" --> E["Map Normative Protocol Constraints from Specification"]
    D -- "No" --> F{"Tier 3: Academic Papers / Formal Specifications (arXiv, TLA+)?"}
    F -- "Yes" --> G["Extract Mathematical Theorems & State Transitions"]
    F -- "No" --> H["Halt Sequence: Insufficient Constraints to Warop IBC"]

Tier 1: Production-Grade Code (Permissively Licensed)

• Search for active open-source projects on GitHub that implement the pattern or algorithm.
• Look for high maintenance signals: active commits, issues resolved, star density, and test suite coverage.
• Confirm permissive licensing (e.g., MIT, Apache 2.0, BSD-3-Clause). Do not read copy-restricted code (e.g., GPL, AGPL, proprietary) to avoid licensing contamination.

Tier 2: Official Standards & RFCs

• If no permissive implementation exists, locate the defining standard (e.g., IETF RFCs, W3C specifications, IEEE standards).
• Extract normative constraints using BCP 14/RFC 2119 keywords (MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, OPTIONAL).

Tier 3: Academic Literature & Formal Models

• If no standard exists, search peer-reviewed research repositories (arXiv, ACM Digital Library, IEEE Xplore) or formal specification repos (e.g., TLA+ specifications, Alloy models).
• Extract proven liveness and safety invariants, pseudocode transition rules, and state machine constraints.

The Termination Gate

If no verified prior art, standard, or literature can be located for a highly complex algorithm, you MUST halt and transition to manual clarification. Greenfield sequence walks without empirical or mathematical groundings are forbidden.

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2. Git Cloning Sanity Guidelines

To inspect codebases in the wild without cluttering the local workspace, you must adhere to the following git cloning rules:

A. Workspace Isolation

• All external clones must reside in a dedicated workspace directory named .prior_art_cache/.
• Cloning to directories outside the workspace (such as /tmp/ or /home/) is strictly prohibited.

B. Network & Storage Optimization

• Shallow Clones (--depth 1): Always append --depth 1 to git clone to avoid downloading historical commits and large historical objects.
• Sparse Checkouts: If only specific files or subdirectories are needed, configure a sparse checkout to retrieve only those files.

Sparse Clone Template Command:

# 1. Clone without checking out files, using blobless filtering
git clone --depth 1 --filter=blob:none --sparse --no-checkout <repo_url> .prior_art_cache/<repo-name>

# 2. Configure sparse checkout paths
cd .prior_art_cache/<repo-name>
git sparse-checkout set <target-directory-or-file>

# 3. Checkout target files only
git checkout

C. Cleanup Lifecycle

• Purge Gate: Cloned repositories are temporary staging buffers.
• You MUST run rm -rf .prior_art_cache/ before executing any commit boundary or finalizing a task. No external source code repositories may remain in the active workspace at commit boundaries.

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3. Document Findings in the Active Sketch

When prior art is located and utilized, record findings in the active sketch ledger. For each source, capture: the URL or citation, the architectural/design pattern or algorithm, its key strengths, how its invariants will be adapted to the target codebase, and the license (MIT, Apache-2.0, BSD-3-Clause). For literature, record the title, DOI or arXiv/RFC identifier, the proven safety or liveness invariants extracted, and any pseudocode or state-machine parameters.

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4. Invariant Auditing (The Copy-Paste Guard)

Do not copy code directly from external repositories. All extracted prior art must be audited against:

1. Spatial Simplicity (Hickey Audit): Enforce that the imported logic is decoupled from the external codebase's dependencies and complected abstractions.
2. Temporal Volatility (Lowy Audit): Ensure that the imported logic aligns with our target module's axes of change and boundaries.