Variants Inherit Down — Copy-and-Adapt Pattern · Pippa Quest

Copy-and-adapt, not import-and-share

Each variant's routes/chat.py is a deliberate copy of the Claude route. They share the pattern (JSONL ground truth, SQLite store, ChromaDB embedding, healing) but own their own code. No shared helper extraction across variants.

Why no shared helper

Shared helpers in this layer would force every variant through a lowest-common-denominator interface — exactly what Rule 1 forbids. Each variant evolves independently. If three variants discover they need the same change, the third is the one that proves the pattern is worth extracting. Until then: copy.

Tool bridge is brain-agnostic

Tool execution is where sharing starts to pay, and even there it follows the rule above. Each variant keeps its own tool_bridge.py; the helpers they genuinely have in common live in one shared module beside them, variants/tool_bridge_common.py. Local Read/Write/Edit/Bash execution is the same whichever brain asked for it — and Claude does not use a bridge at all, because its tools run inside the SDK. The variant-specific part is schema format conversion (OpenAI for Codex/Ollama, function_declarations for Gemini, wrapping for Ollama).

The principle: Sharing is correct when the thing being shared is genuinely the same. Tool execution is the same. Wire format is not. Knowing the difference is the architectural skill.

EV v11 · 2026-10-12: The "third one proves it" rule fired twice in one week, one level below the routes. On 2026-10-02 the family tools that every vessel carries stopped being wired by hand into each bridge: seven copies of the same block per door became one row each in a registry (lesson 11). On 2026-10-04 the six bridges' Bash execution moved onto one shared runner that stops a command's whole process group, because the copied subprocess.run left children running after a timeout (backend track, lesson 8). Both moves kept the line this lesson draws. The route files are still deliberate copies, because their wire formats really differ; what moved was code that was already identical in all six and had been copied only because no one had counted the copies.

Variants Inherit Down — Copy-and-Adapt Pattern

Copy-and-adapt, not import-and-share

Why no shared helper

Tool bridge is brain-agnostic

Progress

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