Debug Endpoint

The debug endpoint runs the routing classifier on a prompt and returns the full decision - without making any provider call or consuming any credits. Use it to understand why a prompt was routed to a particular tier, or to verify that your tier floor and ceiling settings are working as expected. Endpoint:

POST https://api.routor.io/v1/routing/debug

Request

{
  "prompt": "Prove that the square root of 2 is irrational.",
  "system_prompt": "You are a math tutor.",
  "max_output_tokens": 1024,
  "tools": [],
  "messages": [{ "role": "user", "content": "Prove that the square root of 2 is irrational." }]
}

Field	Required	Description
`prompt`	Yes	The user message to classify
`system_prompt`	No	System prompt - affects context length estimate
`max_output_tokens`	No	Expected output length - affects cost estimate
`tools`	No	Tool definitions - used to detect the tool-calling scenario and rerank models by function-calling accuracy
`messages`	No	Full conversation. Defaults to a single user message built from `prompt`. Used for history-floor detection and tool-scenario classification
`profile`	No	Routing profile: `auto` (default)

Response

{
  "decision": {
    "model":          "deepseek/deepseek-v4-pro",
    "tier":           "COMPLEX",
    "category":       "math",
    "confidence":     0.91,
    "method":         "rules",
    "reasoning":      "rules: score=0.340, confidence=0.91, signals=[reasoning (proof, theorem), ...]",
    "costEstimate":   0.0042,
    "baselineCost":   0.0280,
    "savings":        0.85,
    "filteredChain": [
      "deepseek/deepseek-v4-pro",
      "openai/gpt-5.5",
      "anthropic/claude-opus-4.8"
    ],
    "profile":        "auto",
    "historyFloor":   null,
    "toolScenario":   null,
    "bfclScore":      null
  }
}

Response Fields

All fields are nested under a decision object.

Field	Description
`tier`	Assigned tier: NANO, SIMPLE, LIGHT, STANDARD, or COMPLEX
`confidence`	How confident the classifier is, from 0 to 1
`model`	The model that would be selected for this request
`category`	Detected task category (e.g. `math`, `coding_general_debugging_refactoring_testing`, `simple_qa`)
`method`	How the tier was decided: `rules` (rule-based classifier)
`reasoning`	Human-readable explanation of the decision, including score, signals, and any applied overrides
`costEstimate`	Estimated cost in USD for this request on the selected model (including the routing markup)
`baselineCost`	What this would cost on the baseline model (Claude Opus 4.8)
`savings`	Fraction saved vs baseline, from 0 to 1
`filteredChain`	Ordered list of models that would be tried - primary first, fallbacks after
`profile`	Routing profile used: `auto`, `tier`, or `direct`
`historyFloor`	Tier floor applied from conversation history, if any (null when not applicable)
`toolScenario`	Detected tool-calling scenario (`single`, `parallel`, `multi_turn`, `web_search`, `memory`, `optional`), or null when no tools are present
`bfclScore`	The selected model’s BFCL score for the detected tool scenario, or null

Example: Debugging a Misclassification

If a prompt is routing to an unexpected tier, call the debug endpoint to inspect the decision:

curl https://api.routor.io/v1/routing/debug \
  -H "Authorization: Bearer sk-routor-YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "What is a callback function?",
    "max_output_tokens": 512
  }'

Response:

{
  "decision": {
    "model":          "moonshot/kimi-k2.6",
    "tier":           "LIGHT",
    "category":       "coding_general_debugging_refactoring_testing",
    "confidence":     0.78,
    "method":         "rules",
    "reasoning":      "rules: score=0.120, confidence=0.78, signals=[code (function), ...]",
    "costEstimate":   0.0003,
    "baselineCost":   0.0062,
    "savings":        0.95,
    "filteredChain": [
      "moonshot/kimi-k2.6",
      "google/gemini-3.5-flash",
      "deepseek/deepseek-v4-flash"
    ],
    "profile":        "auto",
    "historyFloor":   null,
    "toolScenario":   null,
    "bfclScore":      null
  }
}

If the tier feels wrong for your use case, you can override it with a routor_tier_floor on the request or save a Routing Profile with the right constraints.

Authentication

Same as all other endpoints:

Authorization: Bearer sk-routor-YOUR_KEY_HERE

​Request

​Response

​Response Fields

​Example: Debugging a Misclassification

​Authentication

Request

Response

Response Fields

Example: Debugging a Misclassification

Authentication