Inferensys

Prompt

Structured Error Body Extraction Prompt

A practical prompt playbook for extracting error codes, messages, details, and remediation hints from raw API error payloads into a normalized schema with field-level confidence scoring.
Developer doing prompt engineering on laptop, prompt variations visible on screen, casual coding session.
PROMPT PLAYBOOK

When to Use This Prompt

Understand the ideal use case, required context, and limitations of the Structured Error Body Extraction Prompt before integrating it into your error processing pipeline.

This prompt is designed for API consumers and integration engineers who need to parse heterogeneous error responses programmatically. It extracts error codes, messages, details, and remediation hints from raw API error payloads and normalizes them into a consistent schema. Use this when you are building an error aggregation pipeline, a multi-service client library, or an observability dashboard that must consume errors from APIs with different error body formats. The prompt handles undocumented fields, malformed JSON, nested error objects, and vendor-specific extensions.

This prompt is not a replacement for a schema validator or an OpenAPI spec parser. It is a normalization layer that sits between raw HTTP responses and your structured logging or alerting system. Do not use it when you have a strict, single-source API contract and can rely on static parsing—direct deserialization into typed objects is faster and more predictable for known schemas. The prompt adds the most value when you are consuming errors from multiple services, legacy APIs without formal specs, or third-party endpoints where error body formats drift over time. It also serves as a fallback when primary parsing fails, capturing partial structure from malformed payloads that would otherwise be discarded.

Before deploying this prompt, ensure you have access to the raw response body, HTTP status code, and any relevant headers such as Retry-After or rate limit indicators. The prompt expects these as input context. If you are operating in a high-throughput pipeline, consider caching normalized outputs for identical error signatures and implementing a circuit breaker that falls back to raw body logging when the model is unavailable. For regulated environments where error details might contain PII or secrets, apply redaction before the prompt sees the payload, and always log the original response alongside the normalized output for auditability.

PRACTICAL GUARDRAILS

Use Case Fit

Where the Structured Error Body Extraction Prompt works and where it introduces risk. Use these cards to decide if this prompt fits your integration architecture.

01

Good Fit: Normalizing Heterogeneous APIs

Use when: you consume errors from multiple internal services or third-party APIs that use different JSON structures. Guardrail: always preserve the raw original payload in a separate field so downstream systems can audit the normalization step.

02

Bad Fit: Real-Time Incident Response

Avoid when: latency is critical and the extraction prompt adds unacceptable delay to your alerting pipeline. Guardrail: use a deterministic parser for known schemas in the hot path; reserve this prompt for offline cataloging and documentation workflows.

03

Required Inputs: Raw Error Payloads

What to watch: the prompt needs the complete error response body, HTTP status code, and any relevant headers. Guardrail: validate that the input includes the status code before calling the prompt, and handle empty or non-JSON bodies with a fallback schema.

04

Operational Risk: Undocumented Error Fields

What to watch: the model may hallucinate remediation hints or confidence scores for error bodies it has never seen. Guardrail: require field-level confidence scoring in the output schema and flag any extraction with confidence below 0.7 for human review before publishing to runbooks.

05

Operational Risk: Malformed Error Bodies

What to watch: truncated, HTML-wrapped, or plain-text error responses break structured extraction. Guardrail: preprocess the input to detect non-JSON bodies and route them to a separate normalization path before invoking the extraction prompt.

06

Bad Fit: Security-Sensitive Error Review

Avoid when: error bodies may contain stack traces, internal IPs, or database details that should not pass through an external model. Guardrail: redact sensitive fields before sending to the model, or use a local-only deployment for security review workflows.

PROMPT PLAYBOOK

Copy-Ready Prompt Template

A reusable prompt for extracting structured error information from raw API error payloads, with field-level confidence scoring and handling for malformed responses.

This prompt template normalizes heterogeneous API error responses into a consistent, machine-readable schema. It is designed for integration engineers, observability pipeline builders, and SDK developers who need to parse error bodies from multiple services—each with its own format—into a single structured record that downstream systems can consume reliably. The prompt handles common patterns: JSON problem details (RFC 9457), vendor-specific error wrappers, HTML error pages, and even empty or truncated responses. It does not attempt to classify root causes or suggest remediation steps; those are separate downstream tasks that consume this normalized output.

text
You are an error body extraction system. Your job is to parse a raw API error response and produce a structured JSON object. Do not guess. Do not invent fields. When information is missing, mark it as null and set the confidence to 0.0.

## INPUT
Raw error payload:
[RAW_ERROR_BODY]

HTTP status code: [HTTP_STATUS_CODE]

Response content type: [CONTENT_TYPE]

API or service name: [SERVICE_NAME]

## OUTPUT SCHEMA
Return exactly one JSON object with this structure:
{
  "error_code": string | null,
  "error_message": string | null,
  "error_details": array of strings | null,
  "error_category": string | null,
  "http_status_code": number,
  "retryable": boolean | null,
  "retry_after_seconds": number | null,
  "rate_limit_remaining": number | null,
  "rate_limit_reset_epoch": number | null,
  "documentation_url": string | null,
  "request_id": string | null,
  "raw_body_preserved": string,
  "field_confidence": {
    "error_code": number (0.0 to 1.0),
    "error_message": number (0.0 to 1.0),
    "error_details": number (0.0 to 1.0),
    "error_category": number (0.0 to 1.0),
    "retryable": number (0.0 to 1.0),
    "retry_after_seconds": number (0.0 to 1.0),
    "rate_limit_remaining": number (0.0 to 1.0),
    "rate_limit_reset_epoch": number (0.0 to 1.0),
    "documentation_url": number (0.0 to 1.0),
    "request_id": number (0.0 to 1.0)
  },
  "parsing_notes": string | null
}

## EXTRACTION RULES
1. **error_code**: Extract the most specific error code string (e.g., "invalid_api_key", "rate_limit_exceeded", "E1004"). Look in JSON fields named "code", "error_code", "type", "errorType", or the first element of "errors" arrays. If the body is HTML or plain text, set to null with confidence 0.0.
2. **error_message**: Extract the human-readable error description. Prefer the most specific message over generic fallbacks. Look in fields named "message", "error", "detail", "description", or "title".
3. **error_details**: Collect any additional error context such as field-level validation errors, parameter names, or nested error objects. Return as an array of strings. If none found, set to null.
4. **error_category**: Classify into one of: "authentication", "authorization", "validation", "rate_limit", "server_error", "client_error", "not_found", "conflict", "service_unavailable", "unknown". Base this on the HTTP status code and error body content. Do not invent categories.
5. **retryable**: Boolean. True if the error is transient (5xx, 429, some 409s) and the body or headers suggest retry is safe. False for 4xx auth, validation, or not-found errors. Null if unclear.
6. **retry_after_seconds**: Extract from "Retry-After" header if provided in [HEADERS], or from body fields like "retry_after", "retryAfter", "retry_in". Null if not present.
7. **rate_limit_remaining**: Extract from rate limit headers or body fields indicating quota remaining. Null if not present.
8. **rate_limit_reset_epoch**: Unix timestamp (seconds) when the rate limit resets. Extract from headers or body. Null if not present.
9. **documentation_url**: Extract any URL pointing to error documentation. Look for fields named "docs", "documentation_url", "help", "more_info", or "type" when it contains a URI.
10. **request_id**: Extract the request or trace ID for correlation. Look in fields named "request_id", "requestId", "trace_id", "x-request-id", or similar.
11. **raw_body_preserved**: Always include the original raw body as a string, truncated to 4000 characters if longer.
12. **field_confidence**: For each extracted field, assign a confidence score: 1.0 = exact field name match in structured JSON; 0.7-0.9 = extracted via pattern matching or inference; 0.3-0.6 = guessed from context; 0.0 = field is null because no information was available.
13. **parsing_notes**: If the body was HTML, truncated, empty, or in an unexpected format, note it here. Otherwise null.

## CONSTRAINTS
- Do not hallucinate error codes or messages.
- If the body is empty or only whitespace, set all extractable fields to null with confidence 0.0 and note "empty_body" in parsing_notes.
- If the body is HTML, attempt to extract visible error text but set error_code to null with confidence 0.0.
- Preserve the original error string exactly in error_message; do not rewrite or summarize.
- Output only the JSON object. No markdown, no commentary.

## EXAMPLES
[EXAMPLES]

Adaptation guidance: Replace [RAW_ERROR_BODY] with the actual error response string from your HTTP client. [HTTP_STATUS_CODE] should be the integer status code. [CONTENT_TYPE] should be the Content-Type header value (e.g., application/json, text/html). [SERVICE_NAME] is a label for the originating API. The [EXAMPLES] placeholder should be replaced with 2-4 few-shot examples showing correct extraction from your most common error formats—include at least one malformed body and one empty body example. If you have access to response headers, add a [HEADERS] placeholder and include the relevant rate-limit and retry headers. For production use, wrap this prompt in a validation layer that checks the output JSON against the schema before passing it downstream.

What to do next: After pasting this template into your prompt layer, run it against a golden set of 20-30 known error responses from each API you integrate with. Compare the extracted fields against manually labeled ground truth. Pay special attention to field_confidence scores—if confidence drops below 0.7 on critical fields like error_code or retryable, add more examples or refine the extraction rules. Do not ship this prompt without eval coverage for empty bodies, HTML error pages, truncated responses, and nested error arrays.

IMPLEMENTATION TABLE

Prompt Variables

Required inputs for the Structured Error Body Extraction Prompt. Each variable must be populated before the prompt is sent to the model. Validation notes describe how to programmatically verify the input before execution.

PlaceholderPurposeExampleValidation Notes

[RAW_ERROR_BODY]

The raw, unprocessed error response payload from the API. This is the primary input to be parsed and normalized.

{"error":{"code":"INVALID_PARAMETER","message":"The 'email' field is required.","details":[{"field":"email","issue":"missing"}]}}

Must be a non-empty string or valid JSON object. If empty, abort extraction and return a null output. If the input is not parseable as JSON, treat the entire body as an unstructured error message.

[TARGET_SCHEMA]

The normalized output schema definition that the extracted error fields must conform to. Defines the expected structure for error_code, message, details, and remediation.

{"error_code":"string","message":"string","details":"array","remediation":"string","http_status":"integer"}

Must be a valid JSON Schema or a structured object with field names and types. Validate that the schema is parseable before passing it to the prompt. If null, use a default internal schema.

[API_PROVIDER]

The name or identifier of the API that generated the error. Used to apply provider-specific parsing heuristics and to tag the output for aggregation.

"Stripe" or "AWS" or "InternalAuthService"

Must be a non-empty string. If the provider is unknown, use "UNKNOWN". This value is used for logging and routing, not for critical extraction logic, so null is acceptable but discouraged.

[REQUEST_CONTEXT]

Optional context about the API request that triggered the error, such as the endpoint, HTTP method, and request ID. Helps disambiguate generic error messages.

{"endpoint":"/v1/users","method":"POST","request_id":"req_abc123"}

If provided, must be a valid JSON object. Null is allowed. Validate that the request_id field is present if available, as it is critical for tracing. Do not inject synthetic request IDs.

[CONFIDENCE_THRESHOLD]

The minimum confidence score (0.0 to 1.0) required for a field extraction to be considered reliable. Fields below this threshold are flagged for human review.

0.85

Must be a float between 0.0 and 1.0. If null or out of range, default to 0.8. This threshold is applied post-extraction to determine if the output passes automated validation or requires manual triage.

[KNOWN_ERROR_CATALOG]

An optional list of known error codes and their canonical descriptions. Used to match extracted codes against a trusted source and to fill in missing remediation steps.

["RATE_LIMIT_EXCEEDED","INVALID_AUTH","RESOURCE_NOT_FOUND"]

If provided, must be a non-empty array of strings. Null is allowed. Validate that the catalog does not contain duplicates. If a match is found, the canonical description takes precedence over the extracted message.

[LOCALE]

The language or locale code for the output remediation message. Ensures that user-facing hints are generated in the correct language.

"en-US" or "ja-JP"

Must be a valid BCP 47 language tag. If null or invalid, default to "en-US". Validate against a list of supported locales before passing to the prompt to avoid generating mixed-language output.

PROMPT PLAYBOOK

Implementation Harness Notes

How to wire the Structured Error Body Extraction Prompt into a production application with validation, retries, and logging.

The Structured Error Body Extraction Prompt is designed to be called as a post-processing step after your application receives a non-2xx HTTP response from an upstream API. Instead of logging the raw, potentially malformed payload, you route the response body and the expected schema into this prompt to produce a clean, normalized NormalizedError object. This extraction layer should sit between your HTTP client's error handler and your application's logging, alerting, and retry logic. The prompt is stateless and idempotent, making it safe to call multiple times for the same error payload without side effects.

In a typical implementation, wrap the LLM call in a function like extractStructuredError(rawBody: string, statusCode: int, expectedSchema: string) -> NormalizedError. The function should enforce a strict timeout (e.g., 2 seconds) since error extraction is on the critical path for error handling. On failure—whether a timeout, a malformed model response, or a validation error—fall back to a minimal NormalizedError that preserves the raw body in an unparsed_raw field and sets extraction_confidence to 0.0. Log this fallback event as a warning so your team can investigate extraction gaps. For high-throughput systems, consider batching extraction requests or using a smaller, faster model for this task, as the schema is well-defined and the input is bounded.

Before the extracted error reaches any downstream system, validate the output against your NormalizedError schema. Check that error_code is a non-empty string, http_status matches the actual status code received, and remediation_hints is a list of actionable strings. If the field_confidence map shows any required field below your threshold (e.g., 0.7), flag the extraction for human review or route it to a secondary extraction prompt with more explicit instructions. For regulated environments, always log the raw response body alongside the normalized output to maintain an audit trail. Never suppress the original error—the normalized version is an augmentation, not a replacement.

IMPLEMENTATION TABLE

Expected Output Contract

The normalized error object that the prompt must produce. Every field is validated before the output is accepted by downstream systems.

Field or ElementType or FormatRequiredValidation Rule

error_code

string

Must match pattern ^[A-Z_]+$ and exist in the approved taxonomy or be flagged as UNKNOWN

http_status

integer

Must be a valid HTTP status code (100-599); reject if extracted value is outside this range

message_summary

string

Must be non-empty and ≤ 200 characters; truncate and append '…' if longer

source_payload

object

Must be valid JSON; store the raw original error body exactly as received

remediation_hint

string

If present, must be ≤ 500 characters; null allowed when no actionable hint is extractable

confidence_score

float

Must be between 0.0 and 1.0 inclusive; reject values outside this range

extraction_warnings

array of strings

If present, each string must be ≤ 200 characters; null or empty array allowed when extraction is clean

PRACTICAL GUARDRAILS

Common Failure Modes

What breaks first when extracting structured error bodies from raw API payloads, and how to guard against silent failures, schema drift, and hallucinated remediation.

01

Hallucinated Remediation Steps

What to watch: The model invents plausible-sounding fix instructions for undocumented error codes, especially when the raw payload contains only a generic 500 status. Guardrail: Require a confidence field per extracted field. If the error code is not in the known taxonomy, force remediation to null and flag for human review instead of generating speculative guidance.

02

Schema Drift from Vendor-Specific Extensions

What to watch: APIs often include undocumented fields, nested vendor objects, or non-standard error wrappers that break a rigid extraction schema. The model may silently drop these fields or misalign them. Guardrail: Always include a raw_payload passthrough field in the output schema. Run a post-extraction diff check to detect any top-level keys in the input that are absent from the normalized output, and log them as unmapped_fields for schema review.

03

Malformed JSON or Plain-Text Error Bodies

What to watch: Some APIs return HTML, plain-text stack traces, or truncated bodies on gateway timeouts. The model may attempt to parse non-JSON as JSON, producing garbled output or failing silently. Guardrail: Pre-validate the content type and body syntax before the prompt runs. If the body is not valid JSON, route to a separate extraction path that treats the entire body as a raw_message string and sets all structured fields to null with a parse_failed flag.

04

Conflicting or Missing Rate Limit Headers

What to watch: Rate limit headers (Retry-After, X-RateLimit-Reset) may be missing, conflicting, or expressed in different units across services. The model might pick the wrong value or fabricate a default. Guardrail: Extract all rate limit headers into a structured sub-object with explicit unit labels. Apply a deterministic post-processing rule (not model judgment) to resolve conflicts and compute a single recommended_retry_after_seconds value. If all headers are absent, set it to null and do not guess.

05

Over-Normalization of Distinct Error Codes

What to watch: The model collapses semantically distinct error codes (e.g., INSUFFICIENT_FUNDS vs PAYMENT_DECLINED) into a single generic category, losing actionable detail for downstream routing. Guardrail: Provide a closed taxonomy of known error codes as part of the prompt context. Instruct the model to use exact-match mapping only. If no match is found, preserve the original code in a vendor_code field and set the normalized code to UNKNOWN rather than guessing the closest match.

06

Silent Truncation of Long Error Details

What to watch: Stack traces, long validation error lists, or verbose debug output can exceed the model's output length or attention budget, causing mid-field truncation without warning. Guardrail: Set an explicit truncated boolean flag in the schema for each text field. After extraction, check if the original field length exceeds a safe threshold and if the extracted value ends mid-sentence. If truncation is detected, store the full original in a separate full_detail reference field and flag for async processing.

IMPLEMENTATION TABLE

Evaluation Rubric

Use this rubric to test the Structured Error Body Extraction Prompt before shipping. Each criterion targets a specific failure mode common in production error parsing.

CriterionPass StandardFailure SignalTest Method

Schema Compliance

Output matches the [OUTPUT_SCHEMA] exactly; all required fields present and correctly typed.

Missing required fields, extra undocumented fields, or type mismatches (e.g., string where integer expected).

Validate output against the JSON Schema definition. Run on 50+ diverse error payloads including edge cases.

Error Code Extraction Accuracy

Extracted error code matches the canonical code from the raw payload, including vendor-specific or nested codes.

Extracted code is null when a code exists in the payload, or a generic code is returned when a specific one is present.

Compare extracted code to manually labeled ground truth across 100 error samples from different API providers.

Confidence Score Calibration

Confidence scores are >= 0.9 for unambiguous extractions and <= 0.5 for fields inferred from ambiguous or partial data.

Confidence of 1.0 returned for a field that was guessed or hallucinated; confidence of 0.0 returned for a clearly present field.

Run on a set of intentionally malformed payloads. Check that missing or garbled fields receive low confidence scores.

Remediation Hint Relevance

Generated remediation hint is actionable and specific to the extracted error code, not a generic message.

Hint is a generic fallback like 'Contact support' for a well-documented error code, or hint references a non-existent field.

Spot-check 30 outputs. Verify the hint aligns with the error code's known resolution in the source API documentation.

Handling of Malformed JSON

Prompt returns a valid [OUTPUT_SCHEMA] instance with a top-level parse error flag and null fields, not a raw exception.

Model refuses to respond, returns an empty string, or outputs a natural language apology instead of the structured schema.

Send a payload with truncated JSON, unescaped characters, and binary garbage. Assert the output is valid JSON matching the schema.

Undocumented Field Handling

Unknown fields are captured in a dedicated 'raw_fields' or 'extensions' object without breaking schema compliance.

Undocumented fields are silently dropped, or they cause the entire extraction to fail with a validation error.

Provide an error payload with several vendor-specific extension fields. Verify they appear in the designated catch-all output field.

Multi-Error Payload Extraction

All distinct error objects in a payload containing an array of errors are extracted as separate items in the output list.

Only the first error is extracted; subsequent errors are ignored or overwritten.

Send a payload with a JSON array of 3 different error objects. Assert the output list length is 3 and each item is independently correct.

ADAPTATION OPTIONS

Adapt This Prompt

How to adapt

Use the base prompt with a single model call and lighter validation. Focus on extracting the core fields: error_code, message, and details. Skip confidence scoring and remediation hints initially. Accept string outputs and parse them loosely.

code
Extract error_code, message, and details from [ERROR_BODY].
Return as JSON.

Watch for

  • Missing schema checks leading to downstream parse failures
  • Overly broad instructions that pull in HTTP headers or stack traces as "details"
  • Undocumented error bodies producing hallucinated error codes
Prasad Kumkar

About the author

Prasad Kumkar

CEO & MD, Inference Systems

Prasad Kumkar is the CEO & MD of Inference Systems and writes about AI systems architecture, LLM infrastructure, model serving, evaluation, and production deployment. Over 5+ years, he has worked across computer vision models, L5 autonomous vehicle systems, and LLM research, with a focus on taking complex AI ideas into real-world engineering systems.

His work and writing cover AI systems, large language models, AI agents, multimodal systems, autonomous systems, inference optimization, RAG, evaluation, and production AI engineering.