[Research] LLMs already know how to communicate: AXL — 14 models, 91% error recovery, native structured instructions
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Problem Statement
Multi-agent communication in Claude Code uses natural language between orchestrator and subagents. This is verbose (200–350 tokens per 5-step pipeline) and structurally ambiguous — when one model tells another to "create a file with authentication, making sure to include tests," the boundaries between action, target, and constraints are implicit.
This causes three measurable problems:
- Token waste on inter-agent prose that no human reads
- Silent task drift under error conditions (NL errors read fluently even when wrong)
- No pre-execution validation — NL instructions can only be checked by another LLM at inference time
Proposed Solution
We built and evaluated a structured instruction protocol (AXL) that replaces NL between agents:
CRT|1=api.py|#code:lang:py{must:auth}{must:tests}
One line = one operation. Explicit action, target, type, constraints, references.
Evaluation (14 models, 7 developers, 761 runs)
| Metric | Result |
|--------|--------|
| Zero-shot parse accuracy | 95.0% (152/160 perfect, 14 models) |
| Error recovery (K4, N=22) | AXL 91% vs NL 36% (Fisher p=0.024, phi=0.57) |
| Input compression (K8, N=15) | 28–31% shorter with identical constraint compliance |
| Orchestration (K6, N=11) | All models produce valid pipelines, 2.2x compression |
| Generation accuracy | 4.95/5 (N=20, models WRITE valid AXL) |
| Response compression (K2) | NOT significant (Wilcoxon p=0.21) |
Claude-specific findings
- Sonnet: strongest response compression of any model (35% reduction)
- Haiku: 10/10 task completion with AXL vs 0/10 with NL on same benchmark
- Opus: one of only 3 models that execute AXL subagent commands
Critical limitation
Subagent execution fails in 7/10 models — terse AXL interpreted as confirmation, not execution (K6-B).
Paper (NeurIPS format), interactive presentation, 368 tests, and all data available — contact giperzvuk@gmail.com.
Alternative Solutions
Current alternatives for structured agent communication:
| Protocol | Layer | Limitation |
|----------|-------|------------|
| MCP (Anthropic) | Tool integration | Not a message format |
| A2A (Google) | Discovery/routing | No message compression |
| CodeAgents (arXiv:2507.03254) | Pseudocode | ~3.8x more tokens than AXL |
| Raw JSON | Data format | 100% comprehension but 43% larger, no constraints |
None address the message format layer between agents. AXL fills this gap.
Priority
Low - Nice to have
Feature Category
Performance and speed
Use Case Example
Scenario: Developer uses Claude Code with multi-agent orchestration (teams, subagents)
- Orchestrator receives a task: "audit and fix security issues in the API"
- Currently: orchestrator writes ~300 tokens of NL prose per subagent delegation
- With AXL — same task in 5 lines, 147 characters, machine-parseable:
RD|1=src/app.mjs|#code
AUD|2=$1|#code{must:security}
FIX|3=$2|#code{must:minimal}
TST|4=$3|#code{must:node_test}
RPT|5=$2+$4|#text{must:summary}
- The parser validates the pipeline before any model executes it — catching missing references, circular dependencies, contradictory constraints
- Result: 91% error recovery (vs 36% NL), fewer wasted turns, deterministic dependency analysis
Additional Context
Paper: "LLMs Already Know How to Communicate Efficiently: AXL — A Native Protocol for Structured Agent Instructions" (NeurIPS format, PDF attached)
Author: Aleksey I. Zapolskiy, Independent Researcher, Perm, Russia
Contact: giperzvuk@gmail.com | Telegram: @giperzvuk
This research was conducted entirely on Claude Code over one month. The runtime ("Brain") with hooks, compression, and stigmergy has been in continuous production use — dogfooding AXL to build AXL.
- 761 experimental runs across 14 models from 7 developers
- Cross-model peer review conducted (Claude Opus, DeepSeek V3, Llama 4)
- 368 tests, formal EBNF grammar, all data reproducible
Repository access available on request (currently private, Apache 2.0 release planned within 30 days).
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