Peacodec

Toolkit SenSys 2027 submission · under double-blind review

Scaled learning runs on data that is easy to store, share and read back. Peacodec lets agents design expert-level codecs for every modality you care about, beyond images and video.

Paper Data Compression through Agentic Recursive Experimentation

Peacodec logo: a peacock whose tail feathers end in eyespots Peacodec logo: a peacock whose tail feathers end in eyespots
How it works

The agent experiments. The harness judges. Everything the agent may touch runs in a sandbox; the evaluator and the test split stay outside it.

  1. 01 Data Recordings and a neutral description: sample format only, never the dataset's name or subjects.
  2. 02 Agent, sandboxed Inspects the data, writes probes, and builds an encoder and a decoder.
  3. 03 Fixed evaluator Checks the reconstruction, counts every byte the decoder needs, and enforces the time budget.
  4. 04 Score Dev score during the run; the held-out test split is scored afterwards.
Search · E-RSI

Each session starts fresh and builds on the evidence. Experiment-Driven Recursive Self-Improvement keeps every version and a report from every session, instead of one ever-growing conversation.

Baseline Linear

Linear search: one chain of versions while the conversation context keeps growing. conversation context keeps growing →
One long conversationA single chain of versions; every turn re-reads the whole history.

E-RSI Tree

Tree search: fresh sessions branch from any earlier version; dead ends stay in the tree and every node has a report. kept, not lost report
Fresh sessions, shared evidenceOne idea per session, started from any earlier version and guided by the reports.
Agents

Bring your own agent. Peacodec works with most coding agents, proprietary or open-source. An agent is a scaffold plus a model; the data, prompt and evaluator stay the same for every one.

Proprietary Tested

Claude Code

ModelClaude Opus 5.5
Accessvendor CLI

Proprietary Tested

Codex CLI

ModelGPT-6.1 Sol
Accessvendor CLI

Open weights Tested

Qwen Code

ModelQwen3.8-2.4T-A95B
AccessOpenRouter

Open weights Tested

OpenCode

ModelDeepSeek V4 Pro
AccessOpenRouter

Yours Any CLI agent

Your agent

Any coding agent that runs headless in a terminal, with the model of your choice. Add one adapter file, agents/scaffolds/<name>.sh, that says how to start it, where its session log lives and how it counts tokens.

The four tested in the paper run in the same container, with the same tools, network rules and evaluator. Vendor models run at high effort.

Results

Leaderboards arrive once the test splits are scored. Per-task rankings of agent-designed codecs and baselines, with each codec's search tree.

coming soon
Get started

Prepare a run with one command. Set your data and image paths in config.toml, then render a task without starting the agent; drop --dry-run to start it.

bash
$ python3 harness/launch.py --dataset human-motion --goal lossy-nmse \
    --scaffold claude-code --model opus --effort high --prompt default \
    --network tools --hours 3 --max-evals 0 --dry-run
Cite
@inproceedings{peacodec2027,
  title     = {Data Compression through Agentic Recursive Experimentation},
  author    = {Anonymous Author(s)},
  booktitle = {Under review},
  year      = {2027}
}