Inferensys

Prompt

Tool-Call Error Rate Monitoring Prompt Template

A practical prompt playbook for using the Tool-Call Error Rate Monitoring Prompt Template in production AI workflows to track tool invocation failures, classify error types, and calculate error budget burn rates.
Operations team reviewing AI workflow automation on laptop, workflow builder visible, casual office setup.
PROMPT PLAYBOOK

When to Use This Prompt

Defines the operational context, required inputs, and boundaries for using the Tool-Call Error Rate Monitoring prompt in production agent systems.

This prompt is designed for agent platform engineers and AI SREs who need to transform raw production trace data into actionable tool-call error rate reports. Use it when you have a batch of tool-call spans from your observability pipeline and need to produce a structured analysis that includes error rate trends by tool name, failure type classification, argument validation failure breakdowns, and error budget burn rate calculations. The ideal user has access to structured trace exports—typically JSON arrays of spans with tool_name, status, error_type, and timestamp fields—and needs to generate a diagnostic report that feeds into alert definitions and SLO reviews. This prompt assumes you have already extracted tool-call events from your tracing system and can provide them as structured input. It is not a replacement for real-time metric dashboards but serves as a diagnostic and reporting layer that bridges raw trace data and operational decision-making.

Before using this prompt, verify that your input data includes the minimum required fields: tool_name, timestamp, status (success/failure), and error_type where applicable. The prompt works best with batched data covering a defined evaluation window—typically 1 hour, 24 hours, or 7 days—aligned with your SLO reporting cadence. If your traces lack structured error classification or argument validation metadata, the prompt will still produce a partial analysis but will flag missing dimensions rather than hallucinating values. Do not use this prompt for real-time alerting; it is a batch analysis tool. For live threshold monitoring, pair this with a streaming metrics pipeline and use the output of this prompt to calibrate alert conditions. The prompt also assumes single-tenant analysis: if you are processing traces across multiple tenants or applications, run separate analyses to avoid cross-contamination of error budgets.

After running this prompt, you should have a structured report suitable for inclusion in an SLO review document or as input to an alert configuration workflow. The next step is to validate the output against your known error budget policies and compare the burn rate calculations with your incident response thresholds. Avoid using this prompt when you need sub-second latency on error detection—this is a diagnostic tool, not a real-time circuit breaker. If your tool-call volume exceeds 100,000 spans per batch, consider pre-aggregating by tool name and hour before passing data to the prompt to stay within context window limits. For high-risk production systems where tool failures can cause user-facing incidents, always have a human review the burn rate severity classification before triggering an incident response.

PRACTICAL GUARDRAILS

Use Case Fit

Where this prompt works and where it does not.

01

Good Fit: Structured Trace Ingestion

Use when: You have production traces with structured tool-call spans, error codes, and timestamps. The prompt excels at parsing known schemas to compute error rates, classify failure types, and calculate burn rates. Guardrail: Validate that your trace pipeline emits the required fields (tool_name, error_type, latency_ms) before invoking the prompt.

02

Bad Fit: Unstructured Log Files

Avoid when: Your only data source is raw, unstructured application logs without pre-parsed tool-call events. The prompt is not a log parser; it requires structured input. Guardrail: Implement a pre-processing step to extract tool-call spans into a structured format (JSON) before feeding data to this monitoring prompt.

03

Required Inputs

What to watch: The prompt requires a specific data contract: a list of tool-call events with tool_name, status (success/failure), error_type, and timestamp. Missing fields will cause hallucinated aggregations. Guardrail: Use a strict input schema validator in your application code to reject malformed trace batches before they reach the model.

04

Operational Risk: Silent Calculation Errors

Risk: LLMs can make arithmetic mistakes when calculating error budgets, burn rates, or time-to-exhaustion, leading to false confidence in SLO compliance. Guardrail: Never trust raw numeric outputs. Post-process the model's output with a deterministic function to recalculate all metrics and burn rates from the source data before displaying them in a dashboard or triggering an alert.

05

Operational Risk: Threshold Blindness

Risk: The prompt may fail to flag a critical error rate spike if the spike occurs in a low-volume tool, masking a systemic issue. Guardrail: Configure the prompt to report both absolute error counts and error rates per tool. Implement a secondary check in your alerting system for any tool exceeding a minimum absolute error threshold, regardless of its rate.

06

Operational Risk: Stale Error Taxonomies

Risk: The prompt's failure type classification relies on a known set of error types. Newly introduced tool errors will be bucketed into an "unknown" category, hiding emerging failure modes. Guardrail: Schedule a weekly review of the "unknown" error bucket. Use a separate prompt to analyze these unknowns and propose updates to the classification taxonomy.

PROMPT PLAYBOOK

Copy-Ready Prompt Template

A copy-ready prompt template for analyzing tool-call error rates, classifying failures, and calculating error budget burn from production trace data.

This prompt template is designed to be pasted directly into your monitoring workflow. It instructs the model to analyze a batch of production traces, focusing exclusively on tool-call invocations. The goal is to produce a structured report that identifies error rate trends by tool name, classifies failure types, and calculates the error budget burn rate. Replace every square-bracket placeholder with your specific trace data, tool catalog, and SLO configuration before execution.

text
You are an AI SRE analyzing production traces for an AI agent. Your task is to monitor tool-call error rates.

## INPUT DATA
[TRACE_DATA]

## CONFIGURATION
Tool Catalog: [TOOL_CATALOG]
SLO Target (success rate): [SLO_TARGET]%
Evaluation Window: [EVALUATION_WINDOW]
Error Budget: [ERROR_BUDGET] minutes of downtime or failed calls

## TASK
1.  **Calculate Error Rates:** For each tool in the Tool Catalog, calculate the error rate as (failed calls / total calls) * 100 within the Evaluation Window.
2.  **Classify Failures:** Categorize each failed tool call into one of the following failure types:
    - `INVALID_ARGUMENT`: The model provided malformed or incorrect arguments.
    - `TOOL_NOT_FOUND`: The model attempted to call a non-existent tool.
    - `EXECUTION_FAILURE`: The tool was found and arguments were valid, but the tool's execution returned an error.
    - `TIMEOUT`: The tool call exceeded its allowed execution time.
    - `PERMISSION_DENIED`: The agent lacked the authorization to execute the tool.
3.  **Calculate Error Budget Burn Rate:** Determine the rate at which the error budget is being consumed. The burn rate is the percentage of the error budget consumed within the Evaluation Window, extrapolated to an hourly rate.
4.  **Identify Top Failure Contributors:** List the top 3 tools with the highest error rates and their primary failure type.

## OUTPUT FORMAT
You must respond with a single JSON object conforming to this schema:
{
  "evaluation_window": "string",
  "slo_target_percent": number,
  "overall_error_rate_percent": number,
  "error_budget_burn_rate_percent_per_hour": number,
  "tool_error_breakdown": [
    {
      "tool_name": "string",
      "total_calls": number,
      "failed_calls": number,
      "error_rate_percent": number,
      "failure_type_breakdown": {
        "INVALID_ARGUMENT": number,
        "TOOL_NOT_FOUND": number,
        "EXECUTION_FAILURE": number,
        "TIMEOUT": number,
        "PERMISSION_DENIED": number
      },
      "primary_failure_type": "string"
    }
  ],
  "top_failure_contributors": [
    {
      "tool_name": "string",
      "error_rate_percent": number,
      "primary_failure_type": "string"
    }
  ],
  "alert_triggered": boolean,
  "alert_reason": "string or null"
}

## CONSTRAINTS
- Only analyze tool-call spans within the provided [TRACE_DATA]. Ignore other spans.
- If a tool is not present in the [TOOL_CATALOG], flag it as `TOOL_NOT_FOUND`.
- If the error budget burn rate exceeds a critical threshold of 10% per hour, set `alert_triggered` to `true` and explain the reason.
- Base all calculations strictly on the provided data. Do not infer or assume data not present in the trace.

To adapt this template, start by replacing [TRACE_DATA] with a structured JSON array of your trace spans. Ensure each span object includes name, attributes (containing tool call details and error messages), and status. The [TOOL_CATALOG] should be a simple list of approved tool names. Set [SLO_TARGET] to your agreed-upon success rate (e.g., 99.9) and [EVALUATION_WINDOW] to the time range you are monitoring (e.g., 'last 1 hour'). The [ERROR_BUDGET] must be a concrete number representing your allowed failures. For high-stakes production environments, always route the output of this prompt to a validation step that checks the JSON schema before forwarding alerts to an on-call system. A common failure mode is an incorrect burn rate calculation; verify the math with a separate script if this metric directly triggers paging.

IMPLEMENTATION TABLE

Prompt Variables

Each placeholder must be populated before the prompt is sent. Validation notes describe what the model expects.

PlaceholderPurposeExampleValidation Notes

[TRACE_DATA]

Raw production trace spans containing tool-call events, timestamps, and error codes

{"spans": [{"tool_name": "search_api", "status": "error", "error_code": "TIMEOUT"}]}

Must be valid JSON array with tool_name, status, and timestamp fields per span. Reject if spans array is empty or missing required fields.

[TIME_WINDOW]

Evaluation period for error rate calculation and trend analysis

last_7_days

Must match one of: last_24_hours, last_7_days, last_30_days, or custom ISO 8601 range. Reject unrecognized window values.

[ERROR_BUDGET_TARGET]

SLO target percentage for tool-call success rate

99.5

Must be float between 0 and 100. Reject values below 90 without explicit override flag. Validate precision matches organizational SLO format.

[BURN_RATE_THRESHOLD]

Multiplier defining critical error budget consumption rate

10x

Must be positive number or string like 5x, 10x, 14.4x. Reject values below 1x. Validate against incident response policy thresholds.

[TOOL_NAMES]

Filter scope for specific tools to monitor or null for all tools

["search_api", "database_query", "file_reader"]

Must be JSON array of strings or null. Reject if array contains tool names not present in trace data schema. Null triggers all-tool analysis.

[FAILURE_CLASSIFICATION_SCHEMA]

Taxonomy for categorizing tool-call failures

["timeout", "auth_error", "malformed_args", "rate_limit", "unknown"]

Must be JSON array of unique strings. Reject if empty. Validate that schema covers error_code values present in trace data. Unknown category required as catch-all.

[ALERT_SEVERITY_MAP]

Mapping of burn rate ranges to alert severity levels

{"critical": 10, "warning": 5, "info": 2}

Must be JSON object with severity keys and numeric burn rate thresholds. Reject if critical threshold is lower than warning. Validate alignment with incident response severity definitions.

[OUTPUT_FORMAT]

Desired structure for monitoring output

dashboard_metrics

Must match one of: dashboard_metrics, alert_payload, incident_report, trend_summary. Reject unrecognized formats. Dashboard format requires time-series schema; alert format requires severity field.

PROMPT PLAYBOOK

Implementation Harness Notes

How to wire the tool-call error rate monitoring prompt into an observability pipeline with validation, retries, and alert routing.

This prompt is designed to run as a scheduled evaluation step inside your existing observability stack, not as a one-off debugging query. It expects a batch of production trace spans—specifically tool-call events with their status codes, error messages, argument payloads, and timestamps—as structured input. The prompt's job is to classify failures, compute error rates by tool, and calculate error budget burn rates against your defined SLO targets. Wire it into a cron-triggered workflow (e.g., a GitHub Action, Airflow DAG, or AWS Step Function) that queries your trace store (Datadog, Grafana Tempo, or a custom log sink), formats the spans into the [TRACE_SPANS] placeholder, invokes the model, and routes the output to your alerting platform.

Validation and retry logic is critical because this prompt produces structured JSON that downstream alert rules consume. Implement a post-generation validation step that checks: (1) the output parses as valid JSON matching the expected schema, (2) all error_rate values are floats between 0 and 1, (3) burn_rate calculations are non-negative, and (4) failure_type classifications match your internal taxonomy. If validation fails, retry once with the validation errors appended to the [CONSTRAINTS] field. If the retry also fails, log the raw output and escalate to the on-call channel rather than silently dropping the monitoring window. For high-severity findings—burn rates above 5x or error rates crossing critical thresholds—route the structured alert payload directly to PagerDuty or your incident management platform with the trace correlation IDs attached.

Model choice and latency considerations matter here. This prompt performs classification and arithmetic reasoning over structured data, not creative generation. A fast model (e.g., Claude 3.5 Haiku, GPT-4o-mini, or a fine-tuned Llama variant) is usually sufficient and keeps per-window costs low. Set a 30-second timeout and a token limit appropriate for your batch size. If your trace volume is high, shard the input by tool name or time window and run parallel invocations. Log every invocation—input span count, output summary, validation status, and model latency—to your observability platform so you can detect when the monitoring prompt itself degrades. Finally, maintain a versioned prompt registry so that changes to the failure taxonomy or SLO targets are tracked alongside the prompt template, and run a weekly dry-run against a historical golden set of known-good and known-bad trace batches to catch regressions before they affect production alerting.

IMPLEMENTATION TABLE

Expected Output Contract

Fields, format, and validation rules the output must satisfy before it can be used downstream in alerting pipelines or dashboards.

Field or ElementType or FormatRequiredValidation Rule

error_rate_summary

Array of objects

Each object must contain tool_name (string), error_rate (float 0.0-1.0), and total_calls (integer). Array must not be empty.

error_rate_summary[].tool_name

string

Must match a tool name present in the [TOOL_CALL_TRACE_DATA] input. Non-empty, trimmed.

error_rate_summary[].error_rate

float

Value must be between 0.0 and 1.0 inclusive. Calculated as failed_calls / total_calls for the tool.

failure_type_classification

Array of objects

Each object must contain failure_type (enum), count (integer), and affected_tools (array of strings). Sorted by count descending.

failure_type_classification[].failure_type

enum string

Must be one of: 'argument_validation_error', 'tool_not_found', 'permission_denied', 'timeout', 'rate_limit', 'schema_mismatch', 'unknown'. No custom values allowed.

argument_validation_breakdown

Array of objects

If present, each object must contain tool_name (string), argument_name (string), failure_count (integer), and example_errors (array of strings, max 3). Null if no argument errors.

error_budget_burn_rate

object

Must contain current_burn_rate (float), time_to_exhaustion_hours (float or null), and severity (enum: 'normal', 'warning', 'critical'). Burn rate calculated against [SLO_TARGET].

analysis_timestamp

ISO 8601 string

Must be a valid ISO 8601 datetime string in UTC. Represents the end of the evaluation window defined by [EVALUATION_WINDOW_MINUTES].

PRACTICAL GUARDRAILS

Common Failure Modes

Tool-call error rate monitoring fails silently when trace instrumentation is incomplete, error taxonomies drift, or thresholds are calibrated against unrealistic baselines. These cards cover the most common production failure patterns and how to prevent them before they reach an incident channel.

01

Incomplete Trace Instrumentation

What to watch: The prompt reports a healthy error rate because failed tool calls are not instrumented or are logged without error tags. Missing spans create a false sense of reliability. Guardrail: Validate that every tool-call span includes a status, error_type, and latency_ms field before the monitoring prompt runs. Reject traces that lack required fields and alert on instrumentation gaps separately from error rate alerts.

02

Error Taxonomy Drift

What to watch: New failure modes appear in production but the prompt's classification logic only recognizes old categories, lumping novel errors into a generic 'other' bucket that masks emerging problems. Guardrail: Run a weekly unclassified-error review prompt that samples 'other' failures, proposes new taxonomy categories, and flags when the 'other' bucket exceeds 5% of total errors for human review.

03

Threshold Anchoring to Unrealistic Baselines

What to watch: Error rate thresholds are set against a single quiet week of traffic, causing alert storms when normal seasonal or diurnal patterns produce higher error volumes. Guardrail: Require at least 30 days of historical trace data for baseline calculation, include day-of-week and hour-of-day stratification, and use rolling percentile windows rather than fixed absolute thresholds.

04

Argument Validation Failures Masked as Tool Errors

What to watch: The prompt reports a high tool-call error rate but cannot distinguish between genuine API failures and malformed arguments that the model should have caught before invocation. Operations teams waste time investigating downstream services when the root cause is a prompt or schema mismatch. Guardrail: Add a pre-invocation argument validation check in the trace span and classify failures as 'argument_validation' vs 'tool_execution' before the monitoring prompt aggregates error rates. Route each class to the correct team.

05

Error Budget Burn Rate Miscalculation

What to watch: The prompt calculates burn rate using a fixed window that does not align with the SLO period, producing burn rate alerts that are either too sensitive or too slow to catch rapid exhaustion. Guardrail: Validate that the burn rate calculation uses the same evaluation window and SLO target period defined in the team's error budget policy. Include a burn rate reasonableness check: if the prompt predicts exhaustion in under 5 minutes, flag for human review before paging.

06

Tool Retry Inflation of Error Counts

What to watch: Automatic retry logic inflates raw error counts, making the error rate appear higher than the user-experienced failure rate. The prompt treats each retry as an independent error, triggering false alarms. Guardrail: Deduplicate errors by trace_id and tool_call_index before calculating error rates. Report both 'raw error count' and 'unique failure count' as separate metrics, and base alerts on unique failures unless retry storms themselves are the signal of interest.

IMPLEMENTATION TABLE

Evaluation Rubric

Run these checks against a known set of tool-call spans with pre-calculated expected values before deploying the Tool-Call Error Rate Monitoring Prompt to production.

CriterionPass StandardFailure SignalTest Method

Error Rate Calculation Accuracy

Computed error rate matches pre-calculated value within ±0.5 percentage points for a batch of 100 spans with 12 known failures

Output error rate deviates from expected value by more than 0.5pp; burn rate calculation uses wrong denominator

Run prompt against a golden trace batch with exactly 12 injected tool-call failures and compare output to 12.0% expected error rate

Tool Name Grouping Completeness

Every distinct tool name present in the input spans appears in the output breakdown with a non-null error count

A tool name from the input spans is missing from the output; tool name is truncated or hallucinated

Parse output JSON and assert set of tool names matches the distinct tool names in the golden input spans exactly

Failure Type Classification Accuracy

Each failure is assigned exactly one of the predefined categories: timeout, auth_error, invalid_argument, tool_not_found, or unknown; classification matches golden labels for 95% of cases

Failure assigned to wrong category; multiple categories assigned to single failure; category not in allowed enum

Compare each failure's classified type against pre-labeled golden classifications; require 95% exact match rate

Argument Validation Breakdown Correctness

Count of invalid_argument failures matches pre-counted total; per-parameter breakdown sums to that total

Per-parameter counts do not sum to total invalid_argument count; parameter names are hallucinated

Sum all per-parameter counts and assert equality with total invalid_argument count; verify parameter names exist in tool schema definitions

Error Budget Burn Rate Calculation

Burn rate equals error count divided by error budget for the evaluation window; severity classification matches threshold table

Burn rate uses wrong time window; severity misclassified relative to defined thresholds; division by zero when error budget is zero

Compute burn rate manually from golden data and assert output matches; verify severity label against [BURN_RATE_THRESHOLDS] mapping

Span Timestamp Range Handling

Output covers only spans within the specified [TIME_WINDOW_START] and [TIME_WINDOW_END]; no spans outside range are counted

Spans outside the time window are included in error counts; time window boundaries are ignored

Inject 5 spans with timestamps outside the window into golden batch; assert those spans are excluded from all output counts

Output Schema Compliance

Output is valid JSON matching the [OUTPUT_SCHEMA] exactly; all required fields present with correct types

Missing required field; field has wrong type; extra undeclared fields present; JSON is malformed

Validate output against [OUTPUT_SCHEMA] using a JSON schema validator; assert no validation errors returned

ADAPTATION OPTIONS

Adapt This Prompt

How to adapt

Add strict JSON schema validation, retry logic for malformed outputs, and structured logging of each evaluation run. Wire the prompt into a scheduled job that queries your trace store and writes results to your monitoring dashboard.

Add to [CONSTRAINTS]: Return ONLY valid JSON matching the schema. If a tool has zero errors, include it with count 0. Round burn rates to 2 decimal places.

Add a post-processing step that validates the output against the expected schema before ingestion. If validation fails, retry with the error message appended to [CONTEXT].

Watch for

  • Silent format drift when model versions change
  • Missing tools in the output when error count is zero
  • Burn rate calculation precision errors at low error volumes
  • Timeout on large trace windows; add pagination to [TRACE_DATA]
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.