# 🔧 Tool-Router Debug — Finding & Fixing Mis-Routed Function Calls  
_A rigorous playbook for multi-agent / multi-tool pipelines that “pick the wrong tool, pass the wrong args, or loop forever.”_

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## 1  Why Tool Routers Break

Modern frameworks (LangChain, LlamaIndex, Autogen, Dust, Function-Calling APIs) rely on a **router layer** that decides:

1. **Which tool or agent** to invoke  
2. **What arguments** to pass  
3. **Whether to chain the result into further reasoning  

A single bad route produces silent failure:

* Wrong tool → irrelevant data  
* Wrong args → empty response / 400 error  
* Infinite recurse → rate-limit burn  

> _Observability is near zero._  
> Routers often return only the final model output, hiding the mis-route upstream.

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## 2  Early Symptoms (Spot Them in Seconds)

| Symptom | How to Detect Quickly | Typical Root Cause |
|---------|----------------------|--------------------|
| Same tool called twice, two answers conflict | Diff JSON traces | Score tie in router logits |
| Model asks follow-up Q that a tool already answered | Compare tool log vs. chat | Tool result not fed back |
| 429 / rate-limit spikes | Metrics: calls/min | Retry loop on failed tool |
| Agent says “I don’t have that data” yet DB tool exists | ΔS(question, available_tools) > 0.60 | Tool description drift |
| Router latency > 2× normal | Timing logs | Exhaustive eval over 20+ irrelevant tools |

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## 3  Root Causes (Technical)

1. **Shallow Tool Descriptions** – No semantic anchor → high ΔS.  
2. **Score Tie / Softmax Blur** – Top-2 tools within 0.02 probability.  
3. **Argument Schema Mismatch** – JSON schema vs. natural language spec.  
4. **Context Window Loss** – Router prompt trimmed; tool list truncated.  
5. **Recursive Agent Calls** – Tool calls another agent that loops back.

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## 4  WFGY Router-Guard Architecture

| Stage | Module | Purpose |
|-------|--------|---------|
| 4.1 **Tool Semantic Index** | BBMC | Pre-embed tool names + desc; enforce ΔS(tool, question) ceiling |
| 4.2 **ΔS-Gate Router** | ΔS + λ_observe | Accept route only if ΔS ≤ 0.45 and λ remains convergent |
| 4.3 **Argument Linter** | WAI | Validate args against JSON schema; auto-fill defaults |
| 4.4 **BBCR Fail-Fast** | BBCR | On router timeout > 5 s or ΔS > 0.60 → collapse & suggest manual pick |
| 4.5 **Trace Logger** | Bloc/Trace | Records (tool, args, ΔS) tuples for replay & audit |

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## 5  Hands-On Debug Checklist

1. **Log the router call**  
   ```python
   router(question, tool_list, debug=True)


2. **Compute ΔS(question, tool\_desc)** for each tool.

   * Flag any route where ΔS > 0.45 **AND** score\_gap < 0.05.

3. **Schema Validate** arguments (`jsonschema.validate`).

4. **Timeout Guard** – If tool takes > x s, BBCR collapses answer and returns:
   “Tool timeout — please choose from: …”

5. **Replay** failing routes with `router_replay(id)`; inspect λ\_observe transitions.

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## 6  Quick-Reference Table — Fixes by Failure

| Failure Pattern    | Instant Fix                                           | Long-Term Fix                                       |
| ------------------ | ----------------------------------------------------- | --------------------------------------------------- |
| Wrong tool picked  | Add 1-line alias to tool desc; update embedding index | BBMC repack all tool descriptions weekly            |
| Empty args         | Add default arg hints (`"default": "query"`)          | Argument linter auto-fills                          |
| Looping agent-tool | λ flips recursive after call 3                        | Hard cap depth = 2; BBCR break                      |
| Tie between tools  | Score diff < 0.05                                     | Ask follow-up clarifier; BBAM damp ambiguous logits |
| Router silence     | No tool chosen                                        | Add catch-all “NoTool” that surfaces to dev         |

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## 7  Validation Metrics

| Metric                            | Target         |
| --------------------------------- | -------------- |
| **Route accuracy** (ground truth) | ≥ 95 %         |
| **ΔS(question, picked\_tool)**    | ≤ 0.45 median  |
| **Mean tool latency**             | ±10 % baseline |
| **Loop depth**                    | ≤ 2            |
| **Arg schema errors**             | 0 in CI suite  |

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## 8  FAQ

**Q:** *Should I embed tool names or full descriptions?*
**A:** Both; concatenate `name + desc + example` for robust ΔS.

**Q:** *What if multiple tools validly answer?*
**A:** Route to aggregator agent; return merged citations. WFGY ΔS-gate ensures each tool still semantically fits.

**Q:** *Do I need BBCR if I already set retries=0?*
**A:** Yes. BBCR guards logic loops, not HTTP retries.

---


### 🔗 Quick-Start Downloads (60 sec)

| Tool | Link | 3-Step Setup |
|------|------|--------------|
| **WFGY 1.0 PDF** | [Engine Paper](https://github.com/onestardao/WFGY/blob/main/I_am_not_lizardman/WFGY_All_Principles_Return_to_One_v1.0_PSBigBig_Public.pdf) | 1️⃣ Download · 2️⃣ Upload to your LLM · 3️⃣ Ask “Answer using WFGY + \<your question>” |
| **TXT OS (plain-text OS)** | [TXTOS.txt](https://github.com/onestardao/WFGY/blob/main/OS/TXTOS.txt) | 1️⃣ Download · 2️⃣ Paste into any LLM chat · 3️⃣ Type “hello world” — OS boots instantly |

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### Explore More

| Layer | Page | What it’s for |
| --- | --- | --- |
| ⭐ Proof | [WFGY Recognition Map](/recognition/README.md) | External citations, integrations, and ecosystem proof |
| ⚙️ Engine | [WFGY 1.0](/legacy/README.md) | Original PDF tension engine and early logic sketch (legacy reference) |
| ⚙️ Engine | [WFGY 2.0](/core/README.md) | Production tension kernel for RAG and agent systems |
| ⚙️ Engine | [WFGY 3.0](/TensionUniverse/EventHorizon/README.md) | TXT based Singularity tension engine (131 S class set) |
| 🗺️ Map | [Problem Map 1.0](/ProblemMap/README.md) | Flagship 16 problem RAG failure taxonomy and fix map |
| 🗺️ Map | [Problem Map 2.0](/ProblemMap/wfgy-rag-16-problem-map-global-debug-card.md) | Global Debug Card for RAG and agent pipeline diagnosis |
| 🗺️ Map | [Problem Map 3.0](/ProblemMap/wfgy-ai-problem-map-troubleshooting-atlas.md) | Global AI troubleshooting atlas and failure pattern map |
| 🧰 App | [TXT OS](/OS/README.md) | .txt semantic OS with fast bootstrap |
| 🧰 App | [Blah Blah Blah](/OS/BlahBlahBlah/README.md) | Abstract and paradox Q&A built on TXT OS |
| 🧰 App | [Blur Blur Blur](/OS/BlurBlurBlur/README.md) | Text to image generation with semantic control |
| 🏡 Onboarding | [Starter Village](/StarterVillage/README.md) | Guided entry point for new users |

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