CBCL: Safe Self-Extending Agent Communication

Fuente: arXiv
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Main Author: O'Connor, Hugo
Format: Preprint
Published: 2026
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_version_ 1866915939539222528
author O'Connor, Hugo
author_facet O'Connor, Hugo
contents Agent communication languages (ACLs) enable heterogeneous agents to share knowledge and coordinate across diverse domains. This diversity demands extensibility, but expressive extension mechanisms can push the input language beyond the complexity classes where full validation is tractable. We present CBCL (Common Business Communication Language), an agent communication language that constrains all messages, including runtime language extensions, to the deterministic context-free language (DCFL) class. CBCL allows agents to define, transmit, and adopt domain-specific "dialect" extensions as first-class messages; three safety invariants (R1--R3), machine-checked in Lean 4 and enforced in a Rust reference implementation, prevent unbounded expansion, applying declared resource limits, and preserving core vocabulary. We formalize the language and its safety properties in Lean 4, implement a reference parser and dialect engine in Rust with property-based and differential tests, and extract a verified parser binary. Our results demonstrate that homoiconic protocol design, where extension definitions share the same representation as ordinary messages, can be made provably safe. As autonomous agents increasingly extend their own communication capabilities, formally bounding what they can express to each other is a precondition for oversight.
format Preprint
id arxiv_https___arxiv_org_abs_2604_14512
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CBCL: Safe Self-Extending Agent Communication
O'Connor, Hugo
Cryptography and Security
Artificial Intelligence
Formal Languages and Automata Theory
Logic in Computer Science
D.2.4; D.3.1; F.4.2; F.4.3
Agent communication languages (ACLs) enable heterogeneous agents to share knowledge and coordinate across diverse domains. This diversity demands extensibility, but expressive extension mechanisms can push the input language beyond the complexity classes where full validation is tractable. We present CBCL (Common Business Communication Language), an agent communication language that constrains all messages, including runtime language extensions, to the deterministic context-free language (DCFL) class. CBCL allows agents to define, transmit, and adopt domain-specific "dialect" extensions as first-class messages; three safety invariants (R1--R3), machine-checked in Lean 4 and enforced in a Rust reference implementation, prevent unbounded expansion, applying declared resource limits, and preserving core vocabulary. We formalize the language and its safety properties in Lean 4, implement a reference parser and dialect engine in Rust with property-based and differential tests, and extract a verified parser binary. Our results demonstrate that homoiconic protocol design, where extension definitions share the same representation as ordinary messages, can be made provably safe. As autonomous agents increasingly extend their own communication capabilities, formally bounding what they can express to each other is a precondition for oversight.
title CBCL: Safe Self-Extending Agent Communication
topic Cryptography and Security
Artificial Intelligence
Formal Languages and Automata Theory
Logic in Computer Science
D.2.4; D.3.1; F.4.2; F.4.3
url https://arxiv.org/abs/2604.14512