pontonier

Pontonier is the shared core library for cross-model agent-bridge MCP servers. An agent bridge lets one agent harness call an agent that runs on a different model. Three bridges use this library:

• codex-in-claude — Claude Code → Codex CLI
• moonbridge — Claude Code or Codex → Kimi CLI
• claude-in-codex — Codex → Claude Code CLI

A pontonier is the engineer who builds pontoon bridges: pontonier is not itself a bridge — it is what the bridges are built from.

What is in the box

pontonier.core — backend-agnostic machinery, extracted from the bridges' _core packages:

Rule: pontonier.core never imports from the rest of the package. The gate enforces this with import-linter; src/pontonier/core/__init__.py says why.

pontonier.conventions — the shared vocabulary bridges are built from: error taxonomy + repair rules (envelope), host-parameterized prompt framing (prompts), effect-parameterized tool annotations (annotations), CLI --help feature detection (preflight), and the surface-fingerprint invariant (fingerprint). Wire serialization stays in each bridge.

pontonier.backend — FROZEN (CONTRACT_API_VERSION = 1): the BackendContract static-facts dataclass, the AgentBackend staged run lifecycle (validate_request → prepare → finalize/classify_failure), and a shared failure classifier with fixed precedence. What the freeze permits is stated once, in src/pontonier/backend/__init__.py — read it before changing anything in that package.

pontonier.testing — importable, framework-agnostic test kit: surface honesty (forbidden-phrase scanning against the built wire), adapter and contract conformance, and sync/async tool-pair parity. Checks return violation lists; wire them into any harness.

Development

This project uses uv. One command runs the whole gate — the same one CI runs:

uv sync
./scripts/check.sh

Setup, the individual gate steps, and the commit format are in CONTRIBUTING.md. Norms and prohibitions for AI agents working in this repository are in AGENTS.md. Releases: docs/releasing.md.