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+# Phase 3: Tier 3-9 Providers - Context
+
+**Gathered:** 2026-04-05
+**Status:** Ready for planning
+**Mode:** Auto-generated (infrastructure phase — discuss skipped)
+
+<domain>
+## Phase Boundary
+
+All 108+ LLM provider definitions exist — specialized models, Chinese/regional providers, infrastructure gateways, emerging tools, code assistants, self-hosted runtimes, and enterprise platforms. Completes the provider library started in Phase 2 (26 Tier 1-2 providers → 108+ total).
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Claude's Discretion
+All implementation choices are at Claude's discretion — pure infrastructure/data phase. Use existing YAML schema and patterns from Phase 2.
+
+### Lessons from Phase 2 (CRITICAL)
+- **Generic regex patterns cause false positives at scale.** Phase 2 Tier 2 providers without distinctive prefixes produced false positives on synthetic test fixtures. With 82 more providers in Phase 3 (mostly generic Chinese/regional/emerging providers), this risk compounds.
+- **Mitigation strategy**:
+  1. Providers WITHOUT distinctive key prefixes MUST rely on keyword pre-filter alone, NOT on overly-broad regex matching.
+  2. Set confidence to "low" or omit regex entirely and use keyword-only detection where no documented key format exists.
+  3. Use HIGH entropy_min (≥4.0) for generic alphanumeric patterns.
+  4. Test each provider's regex against existing testdata/samples/ fixtures to prevent regression.
+- **Category field**: still not in schema.go — YAMLs should OMIT category field unless schema is updated this phase.
+
+</decisions>
+
+<code_context>
+## Existing Code Insights
+
+### Reusable Assets
+- Phase 2 established dual-location pattern: `providers/X.yaml` + `pkg/providers/definitions/X.yaml`
+- pkg/providers/tier12_test.go — guardrail test pattern to replicate for Tier 3-9
+- pkg/providers/schema.go — Provider struct (Name, DisplayName, Tier, FormatVersion, LastVerified, Keywords, Patterns, Verify)
+- 27 existing provider YAMLs in providers/ as templates
+
+### Established Patterns
+- Go `embed.FS` via `go:embed definitions/*.yaml`
+- RE2-only regex (no lookahead, no backrefs)
+- Keywords list non-empty (required for Aho-Corasick pre-filter)
+- patterns with regex, entropy_min, confidence fields
+
+### Integration Points
+- providers/ and pkg/providers/definitions/ — add N new YAML files (likely 82-90)
+- pkg/providers/tier12_test.go — extend or mirror for tier3+ guardrail
+- `keyhunter providers list --tier=enterprise` — requires tier filter support in cmd/providers.go (may need to be added this phase)
+
+</code_context>
+
+<specifics>
+## Specific Ideas
+
+Provider groups to cover (per ROADMAP success criteria):
+- **Chinese/regional**: DeepSeek, Zhipu, Moonshot (Kimi), Qwen (Alibaba), Baidu (Wenxin/ERNIE), ByteDance (Doubao), 01.AI (Yi), MiniMax, StepFun, SenseTime
+- **Self-hosted runtimes**: Ollama, vLLM, LocalAI, llama.cpp, LMStudio, text-generation-webui, Jan, GPT4All
+- **Code assistants**: GitHub Copilot, Cursor, Tabnine, Codeium, Cody (Sourcegraph), Continue, Aider, Phind
+- **Enterprise**: Salesforce (Einstein GPT), ServiceNow (Now Assist), SAP (Joule), Palantir (AIP), Databricks (DBRX), Snowflake (Cortex), Oracle (Generative AI), HPE, IBM Watsonx
+- **Infrastructure gateways**: OpenRouter, LiteLLM, LangSmith, Helicone, PortKey, LangFuse, Traceloop
+- **Specialized**: Perplexity (pplx-), ElevenLabs, AssemblyAI, Deepgram, Speechmatics, Runway, Pika, Stability AI, Midjourney, Ideogram, Leonardo AI, Suno, Udio, PlayHT, Descript
+- **Emerging**: Writer, Jasper, Copy.ai, WordAI, ContentBot, Rytr
+- Aim for 82-90 additional providers to reach 108+ total
+
+</specifics>
+
+<deferred>
+## Deferred Ideas
+
+- `--tier=enterprise` CLI filter: add to Phase 3 if schema already has Tier field, otherwise defer to later
+- Provider "category" enum: defer to a separate phase (schema change)
+- Keyword-only detection mode for providers without documented key formats: lightweight enhancement to pkg/engine/detector.go — consider including if time permits
+
+</deferred>