IMPLEMENTATION_TRACEABILITY.md

Reference implementation traceability

The generalized s&box implementation is maintained separately in sbox-adaptive-director. Its own evidence map is the implementation-side index.

It is clean-room code, not a decompilation. The table below maps reusable components back to evidence in this repository.

flowchart LR
    DLL[Retail server.dll] --> Extract[Reproducible extraction and disassembly]
    Trace[Sanitized runtime traces] --> Claims[Confidence-labeled research claims]
    Extract --> Claims
    Claims --> Library[Configurable clean-room components]
    Library --> Tests[Deterministic tests and real s&box editor gate]

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Implementation component	Evidence in the shipped L4D2 binary	What remains configurable/original
Pressure/team intensity	research/INTENSITY_RECOVERY.md, intensity disassemblies and 209-update validation	Library API/storage
Four-phase tempo	analysis/tempo_state_machine_intensity.json and tempo consumers	Host-facing configuration
Panic waves	RVA 0x0028C400, jump table 0x0028C754, oracle traces	Host spawn requests
Concurrent survival lanes	RVA 0x0028EE00, analysis/survival_scheduler_disassembly.json	Lane definitions/priorities
Scenario/finale orchestration	RVA 0x0028B7C0, analysis/finale_machine_disassembly.json	General stage schema
Encounter composition	uniform due-class selector RVA 0x0026F910; conversion callback RVA 0x00279F40	Weighted composition is an optional clean-room policy
Failed-spawn recovery	explicit boss-creation failure path RVA 0x002881A0, pending-mob RVA 0x00287710	Retry count/delay
Spatial selection/fallback	RVAs 0x00274BC0, 0x002EAEB0, 0x0035F370; PLACEMENT_AND_SPECIALS_RECOVERY.md	Host navigation enumeration and engine traces
Weighted ownership	RVAs 0x002609D0 and 0x0026C520	Generic player/candidate model
Resource population	RVAs 0x00280310, 0x00280750, 0x002812D0, 0x00283C40, 0x00284640	Density targets/categories
Script/mode callbacks	callback region 0x00279D20-0x0027A250, mob-with-boss 0x00289F30, stage/music 0x0028A2B0	Typed generalized interfaces
Adaptive music authority	server Music RVAs 0x002B0030-0x002B3F59, research/MUSIC_DIRECTOR_RECOVERY.md	Host observations, generalized event IDs and replication adapter
Music track runtime	client RVAs 0x0024A630-0x00250DE9, analysis/music_sound_events.json	Audio adapter and clean-room catalog data

Exact Valve source, private symbols, comments, and underdetermined formulas cannot be reconstructed from a stripped optimized retail DLL. The implementation therefore treats directly recovered constants/states as compatibility evidence and isolates uncertain policy behind configuration.

Reproducible validation

Validation was rerun on July 31, 2026 against the installed retail server.dll with SHA-256 a93ec916a8f26fbea85688c321d2ba8dd346d435fab09a0b926dd950c2e1ea12:

• extract_director_evidence.py reproduced the analyzed image layout, named-method references, Director console-variable tokens, and Director RTTI inventory.
• validate_averaged_intensity.py checked 209 native updates. The recovered equation's maximum absolute error was 2.1988299847564e-08.
• recover_placement_and_specials.py verified decisive selection instructions and recovered constants before emitting the semantic record in analysis/placement_and_specials_recovery.json.

These checks establish traceability to shipped machine code and sanitized runtime observations. They do not claim access to Valve's unavailable original source files.

For a deeper audit, start with the function catalog, architecture recovery, system diagrams, and coverage/limits audit.