Agentic development: two AI coding agents porting GoldenEye 007
How this port was actually built: a local open-weight model (Qwen 3.8 on a single RTX 5090) and a hosted frontier model (Claude / Claude Code) handing work back and forth through shared written notes, under one person’s part-time direction. The goal, the setup, the timeline, and an honest read on what did and didn’t work.
Snapshot as of the v0.3.0 milestone (20 Sep 2026; findings through D321). v0.4.0 (28 Sep) extended the timeline with the options/input work — the README’s “How it was made” section carries the final project numbers.
Contents
- Why this project exists
- The setup
- Timeline
- By the numbers; Commit velocity · Who did what
- The handoff workflow
- Assessment
Why this project exists
The playable port is real, but it is not the primary deliverable. The goal was to test how well coding agents hold up on a large, unfamiliar, low-level codebase; one with none of the properties that make web-app work easy for an LLM:
- ~230 translation units of decompiled Nintendo 64 game C, compiled unmodified;
- big-endian, 32-bit, MIPS ABI assumptions throughout, run on a little-endian 64-bit host;
- bugs that surface as a fault or a garbled frame hundreds of milliseconds after the actual cause, often in a different subsystem;
- a graphics coprocessor (the RSP) that has to be emulated in software before anything draws at all.
Concretely it set out to validate a two-agent arrangement: a locally-hosted open-weight model doing the bulk of the work on a single consumer GPU, a hosted frontier model brought in for a collaborative phase, and, the part that turned out most interesting, the two handing work back and forth through shared written artifacts, directed by one human.
The setup
| Local agent | unsloth/Qwen3.8-27B-GGUF:UD-Q4_K_XL on a single NVIDIA RTX 5090, driven mainly through the pi coding agent. Unsloth Desktop (Unsloth’s local model runtime, which can drive agents such as Claude Code) was also trialed but not used significantly. |
| Hosted agent | Claude, via Claude Code, on a Claude Pro subscription; mostly Sonnet 5, with Opus 5 used as an escalation tier for the hardest problems and whenever there was subscription budget to spend on it |
| Human | one person: direction, work partitioning, integration, and every build / playtest / frame-capture the agents could not run |
| Base | fork of the GoldenEye 007 decompilation (years of prior work by Larry Ficken (“kholdfuzion”) and contributors) |
| Reused | the Perfect Dark PC port’s fast3d software RSP; same Rare engine family |
The port is the GoldenEye-specific porting work on top of those two existing bodies of work; it is not a from-scratch reimplementation of either.
In practice the models formed a three-tier escalation — the local model handled well-scoped work, Sonnet 5 took what it stalled on, and Opus 5 the rest; the same “escalate when stuck” move applied at every level.
Timeline
All dates from this repository’s own commit history (August–September 2026).
# phase timeline (from the port's own commit dates)
Aug 16 day 0 fork + PC-port scaffolding
Aug 20 day 4 full compile + link (~230 TUs); boot to window
Aug 22 day 6 first rendered frames; offline asset-conversion pipeline
Aug 24 day 8 entire intro renders (logos -> gun-barrel -> cast)
Aug 27 day 11 Claude joins (handoff workflow begins)
Aug 29 day 13 21 solo levels load + render + unattended no-crash; SDL input layer
Aug 30 day 14 front-end flow (menu -> briefing -> start)
Aug 31 day 14 file-backed EEPROM saves
Sep 02 audio mixer (music + SFX)
Sep 14 Steam Deck hardening + F10 overlay QoL
Sep 18 final fix sweep (D309-D321) + release review
Sep 20 day 35 v0.3.0 released: full campaign at Agent difficulty, audio
complete, bundles for Windows, Linux and Steam Deck
Roughly two weeks, one person part-time, took the decompilation from “builds an N64 ROM” to “boots on desktop, renders every solo level, playable through the front end into the early game”. The rest of month one (29 Aug – 20 Sep) took it from there to a public release: the 21-level sweep to full-campaign completion, the audio mixer, input and Steam Deck polish, widescreen FOV scaling, and the v0.3.0 bundles — with a set of cosmetic issues documented rather than outstanding.
By the numbers
| Calendar time | 36 days (16 Aug – 20 Sep 2026), one person part-time |
| Commits on the port | ~835 |
| Root-caused bugs logged | D1–D321 in findings.md, 199 tracked entries in the index (some labels later merged or withdrawn) |
| Handoff sessions | 190+ (M-2 … M-192, and counting) |
Game-source files given #ifdef PORT ABI edits |
71 files, ~385 blocks |
| New port-layer / tooling files | ~119 |
| Port layer | ~24,450 lines C/C++ (port/) |
| PC asset-conversion tooling | ~7,180 lines Python (tools_pc/) |
| Outcome | v0.3.0 released: full campaign playable end to end (all 21 missions playtested at Agent difficulty) at a steady 60 fps, full audio (music + SFX), file-backed saves; Windows, Linux and Steam Deck; known cosmetic defects documented in the finding log |
Commit velocity
# commits per week (week start)
8/16 ## 20
8/23 ########### 109
8/30 #################### 203
9/6 ############## 141
9/13 ###################### 220
9/20 # 6 (release day only)
(each # ~ 10 commits)
Weekly totals (the final week is release day only). The step up from the 8/23 week onward is the collaborative phase in full swing, including the parallel multi-agent “bursts”; the 9/13–9/19 week peaks on a single-day 84-commit burst (9/15) when the Steam Deck playtest-feedback batch landed at once.
Who did what
# commits by agent (raw count, snapshot through early September)
Claude ################ 161 (72%)
Local model (Qwen 3.8/pi) ###### 62 (28%)
(each # ~ 10 commits)
(Phase A, the first 26 commits, to 24 Aug, was entirely the local model, solo; from 27 Aug on the two agents worked in parallel. The raw tally was not re-run for the final third of the project; treat the milestone-weighted estimate below as the better number.)
| Milestone / workstream | Primary agent | Weight |
|---|---|---|
| PC build system, region macros, full compile + link of ~230 units | local model | large |
Boot chain: ROM map, OS-shim layer (libultra.c), host threads, dual-mapped DRAM |
local model | large |
Software-RSP integration + replacement scheduler (gesched.c) |
local model | medium |
Offline asset-conversion architecture + first converters (tools_pc/) |
local model | large |
| Intro rendering (logos → gun-barrel → cast) | local model | medium |
Stage load unblocked (D69–D87) |
Claude | medium |
21-level crash sweep; ~12 crash classes root-caused (D88–D169) |
Claude | large |
| SDL input layer (keyboard / mouse / gamepad, mouse-look) | Claude | medium |
| Front-end flow (menu → briefing → start), EEPROM saves | Claude | medium |
| Parallel struct-layout / converter static audits | local model | medium |
| Continuing tasks after Claude hit a usage limit | local model | small |
| The hardest structural bugs (matrix handedness, format specs) | Claude | n/a |
| Every build, playtest, frame capture, integration, and direction | human | n/a |
Estimated effort split. The raw commit count above (~28% local / ~72% Claude) undercounts the local model: Phase A landed the build system and boot chain in relatively few, large commits, and the local model kept contributing ~15–20% of Phase B in parallel. Weighting by milestone difficulty rather than raw commits; the foundation is a heavier third of the project than its commit share suggests; the developer’s estimate is roughly:
# agent effort, milestone-weighted
Claude ############ 60%
Local model (Qwen 3.8/pi) ######## 40%
(each # ~ 5%)
The local model’s ~40% is front-loaded and foundational (the build, the boot chain, the RSP wiring, the converter architecture) plus continuous parallel support; Claude’s ~60% is the higher-volume Phase-B debugging, the two big discrete features, and the hardest structural bugs. A 27B open-weight model on one consumer GPU carrying the entire foundation of a project like this is the result worth taking away.
The handoff workflow
This is the part worth paying attention to.
# the handoff workflow
HUMAN
direction, integration, build + playtest verification
| scopes task, budget, files | scopes task, budget, files
v v
CLAUDE (hosted) QWEN 3.8 / pi (local, RTX 5090)
| patch + write-up | patch + write-up
+--------------+ +--------------+
v v
SHARED ARTIFACTS (both agents read + append)
HANDOFF.md . findings.md . porting-notes.md
Both agents worked against the same three written artifacts, which is what let them substitute for each other:
HANDOFF.md; the current state, the immediate next task, and the environment gotchas. Originally a session-to-session note for one agent, it became the interface between the two agents: when Claude reached a usage limit mid-problem, the local model picked the task up from the HANDOFF state and continued; when the local model hit a bug that needed deeper structural reasoning, it wrote up where it was and Claude took over.findings.md; the chronological finding log. 321 numberedDentries by v0.3.0 (199 tracked in the index; some labels merged or withdrawn), each a root cause withfile:lineevidence and the fix. New agents (either model) are pointed at the relevant entries before they start.porting-notes.md; the append-only “recurring bug classes” file. The single highest-leverage artifact: it stopped both models from re-deriving the same class of N64→PC bug over and over.
Around these, the working rules (full detail in
../dev-process.md):
- file-partitioned tasks; each agent’s task scoped to a disjoint set of files so patches never collided;
- visible budgets; every investigation task carried an explicit “N build→run cycles” limit and a defined fallback (revert probes, write up with a confidence rating);
- the human owns verification; building, running the game, capturing a frame, and judging it against N64 reference footage was never delegated.
Assessment
Honest notes, for anyone weighing whether this transfers.
Worked well
- The local model carried the groundwork phase; build system, boot chain, OS shims, and the offline-converter architecture. None of it was rewritten later.
- The written-artifact discipline made agent output compound. An agent starting cold late in the project was more effective than one early on, because the accumulated notes were good. This is also what made the two models interchangeable on a given task.
- Handoff on limit turned Claude’s usage cap from a hard stop into a slowdown; the local model kept the problem moving.
- Bounded behavioural bugs (a truncated pointer, a byte-swap off by one) are a good fit for an agent given a tight loop and a reference to diff against.
Worked poorly / needed the human
- Anything requiring the running game. Build, playtest, capture a frame, decide whether it looks right; that loop was the human’s job throughout, and it was the bottleneck.
- Non-deterministic bugs. Frame-timing stalls and concurrent-build flakiness repeatedly fooled agents into “fixing” regressions that were not real. A number of findings are corrections of earlier findings.
- Long structural bugs (matrix handedness, a whole serialized-format spec) often ended in a “here is what I know, confidence medium” writeup rather than a fix, even with the budget raised.
- The capability gap is a gradient, not a wall. The local model was strong on well-scoped work and weaker when a bug needed several interacting facts held at once; those went to Sonnet 5, and the few that stalled Sonnet went to Opus 5. Each tier earned its place on the problems the tier below it couldn’t close.
Still outstanding: see
docs/ROADMAP.md,
the single tracker for open work.
Since the two-agent phase
The two-agent setup above is the initial phase, snapshotted at v0.3.0 (the project has since shipped v0.4.x and is heading to v0.5.0; the model and harness record below is current through that point).
Since then the emphasis has shifted from “the two models that built it” to testing a lot of new models and harnesses, to find what’s fastest and cheapest per task. The long-time local workhorse stayed Unsloth’s Qwen 3.8 27B; in the final week that broadened into a menu, and the current standard is NInfer + Strata. On the hosted side, the Claude orchestrator stepped up from Sonnet 5 / Opus 5 to the 5.5 tier (Sonnet 5.5 / Opus 5.5, out in the last few weeks), which has driven the most recent work. The local menu:
- Qwen 3.8 27B (Unsloth,
UD-Q4_K_XL) — the primary local workhorse for most of the port’s life, doing nearly all of the local groundwork on its own. A larger-contextISTA-DASLab/Qwen3.8-27B-GSQ-RCO-GGUF(IQ3_S) was also briefly trialed for bigger-context workloads, then shelved (little use since v0.2.0). - NInfer (Windows) (natpate/ninfer-windows, v0.9.0, CUDA 13.1 — a standalone Windows port of the NInfer engine, with MTP / DFlash2 speculative decoding) — ran Qwen 3.8 27B in base, NVFP4 and NVFP4-full artifacts; trialed in the final week, now half of the standard and the fast day-to-day local driver.
- Qwen 3.8 Flash-Next via Strata (Niko1221’s MIT-licensed C++/CUDA/HIP engine) — a 125B mixture-of-experts model that normally needs a server, run locally on a single gaming GPU (IQ1_M, 1-bit) for the biggest-context coding passes. The other half of the standard.
- claude-code-delegate-local — an MCP server that let the Claude Code orchestrator and the local models talk, delegating Claude’s subagents to the local engines. A nice tool, but mostly deprecated now: hand-offs between agents are done by hand for now, pending a better parallel-agent handoff system that drops the MCP overhead.
- GPT-6 (Sol) via OpenRouter — a frontier hosted model, trialed to see how it held up (not the hardest-work tool).
The practical effect: the project stopped depending on any one model or its usage limits. The local GPU is now the default path for high-volume work, with hosted frontier models reserved for the problems the local models can’t close.