[CI] Mode auto-detector errs toward 'full' when no signals match — 5 coordinator overrides in one batch

[akaszubski]

Problem

In the batch of 21 issues (20260521-214143), the coordinator manually overrode auto-detected pipeline modes 5 times:

• Hook recovery: DeprecationWarning silently swallowed in shim — switch to stderr direct write (#972 follow-up) #993: full → fix
• [CI] M-01: command_registered lacks path-traversal guard on caller-supplied name #954: full → fix
• [CI] False-positive lock test pattern (#1007) — document for reuse in future audits #1011: full → light
• fix(hooks): prompt drift threshold fires on multi-round single-issue remediation loops #934: full → fix
• [CI] Implementer embeds plan-critic revision annotations in final document section headers #921: full → fix

All 5 were small bug fixes where "full" mode (8 agents including both researchers) was wasteful. The auto-detector defaulted to "full" because the issue body signals didn't match any lighter-mode heuristics.

Impact

Each unnecessary "full" run versus "fix" run costs 2 extra agents (researcher-local + researcher) per issue. At 4 false-full detections → 8 unnecessary agent invocations per batch. At 1,000 tokens/agent-minute, this is measurable overhead.

Root Cause

The mode detector likely uses presence-of-signals to select lighter modes (e.g., detect "fix" keywords → use --fix) but falls back to "full" on ambiguity. Small bug fixes that don't explicitly say "fix" in the issue body get classified as full.

Suggested Fix

Strengthen the --fix heuristics in the mode detector:

• Issue title starts with fix: or fix( or contains "bug fix", "hardening", "guard" → --fix is a strong prior
• Issue body is under N words with no architecture changes → --fix
• Issue references a specific failing test → --fix
• Issue references a specific line/file → --fix

Alternatively, lower the default from "full" to "fix" when no architecture signals are present, requiring explicit signals for "full" (new feature, new agent, new hook, etc.).

Relevant file: plugins/autonomous-dev/lib/ — mode detector / issue classifier (likely pipeline_mode_detector.py or similar)

Plugin Version: 3.50.0 (f6f264c)

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Filed automatically by continuous-improvement-analyst

[akaszubski]

Implemented in 82e1985 (cluster E — batch mode improvements).