feat: ambient mode detection tweaks — refine lean classification approach

[dean0x]

Overview

After working with the new lean ambient mode architecture (SessionStart classification rules + UserPromptSubmit preamble + router SKILL), there are remaining tweaks to refine. The core approach is solid but needs tuning based on real usage.

Current Architecture

• SessionStart hook injects ~30-line classification rules as additionalContext (once per session)
• UserPromptSubmit hook injects one-sentence preamble per message triggering classification + router loading
• Router SKILL is a pure lookup table (~50 lines) mapping intent×depth to domain and orchestration skills
• Three-tier depth: QUICK (direct response), GUIDED (focused skills), ORCHESTRATED (full agent pipelines)

Areas for Potential Tweaks

Classification accuracy, depth calibration, edge cases, and router mappings may need adjustment after real-world usage. Specific areas to evaluate:

• Intent signal accuracy — are prompts being classified correctly?
• Depth boundaries — is the QUICK/GUIDED/ORCHESTRATED split calibrated right?
• Edge cases — ambiguous prompts, multi-intent messages, follow-ups
• Router skill mappings — are the right skills loading for each intent×depth?
• Preamble wording — is the one-sentence injection effective?

Tasks

• Collect observations from real ambient usage sessions
• Identify misclassification patterns (wrong intent or wrong depth)
• Propose and apply classification rule adjustments
• Propose and apply router mapping adjustments
• Verify changes don't regress existing correct classifications

References

• PR feat(ambient): pipeline flow, SessionStart classification, minimal preamble #174 (ambient pipeline flow — current implementation)
• PR feat(v2): track3 ambient refinements — skill renames, detection-only preamble #172 (ambient refinements — orch renames, TDD enforcement)
• scripts/hooks/session-start-classification — SessionStart hook
• scripts/hooks/preamble — UserPromptSubmit hook
• shared/skills/router/SKILL.md — router skill
• shared/skills/router/references/classification-rules.md — classification rules