promql-generator — скилл для Claude Code: PromQL-запросы и алерты

---
name: promql-generator
description: Generate/create/write PromQL queries, metric expressions, alerting rules, recording rules, Prometheus dashboards.
---

# PromQL Query Generator

## Overview

This skill provides a comprehensive, interactive workflow for generating production-ready PromQL queries with best practices built-in. Generate queries for monitoring dashboards, alerting rules, and ad-hoc analysis with an emphasis on user collaboration and planning before code generation.

## When to Use This Skill

Invoke this skill when:
- Creating new PromQL queries from scratch
- Building monitoring dashboards (Grafana, Prometheus UI, etc.)
- Implementing alerting rules for Prometheus Alertmanager
- Analyzing metrics for troubleshooting or capacity planning
- Converting monitoring requirements into PromQL expressions
- Learning PromQL or teaching others
- The user asks to "create", "generate", "build", or "write" PromQL queries
- Working with Prometheus metrics (counters, gauges, histograms, summaries)
- Implementing RED (Rate, Errors, Duration) or USE (Utilization, Saturation, Errors) metrics

## Interactive Query Planning Workflow

**CRITICAL**: This skill emphasizes **interactive planning** before query generation. Always engage the user in a collaborative planning process to ensure the generated query matches their exact intentions.

Follow this workflow when generating PromQL queries:

### Stage 1: Understand the Monitoring Goal

Start by understanding what the user wants to monitor or measure. Ask clarifying questions to gather requirements:

1. **Primary Goal**: What are you trying to monitor or measure?
   - Request rate (requests per second)
   - Error rate (percentage of failed requests)
   - Latency/duration (response times, percentiles)
   - Resource usage (CPU, memory, disk, network)
   - Availability/uptime
   - Queue depth, saturation, throughput
   - Custom business metrics

2. **Use Case**: What will this query be used for?
   - Dashboard visualization (Grafana, Prometheus UI)
   - Alerting rule (firing when threshold exceeded)
   - Ad-hoc troubleshooting/analysis
   - Recording rule (pre-computed aggregation)
   - Capacity planning or SLO tracking

3. **Context**: Any additional context?
   - Service/application name
   - Team or project
   - Priority level
   - Existing metrics or naming conventions

Use the **AskUserQuestion** tool to gather this information if not provided.

> **When to Ask vs. Infer**: If the user's initial request already clearly specifies the goal, use case, and context (e.g., "Create an alert for P95 latency > 500ms for payment-service"), you may acknowledge these details in your response instead of re-asking. Only ask clarifying questions for information that is missing or ambiguous.

### Stage 2: Identify Available Metrics

Determine which metrics are available and relevant:

1. **Metric Discovery**: What metrics are available?
   - Ask the user for metric names
   - If uncertain, suggest common naming patterns
   - Check for metric type indicators in the name:
     - `_total` suffix → Counter
     - `_bucket`, `_sum`, `_count` suffix → Histogram
     - No suffix → Likely Gauge
     - `_created` suffix → Counter creation timestamp

2. **Metric Type Identification**: Confirm the metric type(s)
   - **Counter**: Cumulative metric that only increases (or resets to zero)
     - Examples: `http_requests_total`, `errors_total`, `bytes_sent_total`
     - Use with: `rate()`, `irate()`, `increase()`
   - **Gauge**: Point-in-time value that can go up or down
     - Examples: `memory_usage_bytes`, `cpu_temperature_celsius`, `queue_length`
     - Use with: `avg_over_time()`, `min_over_time()`, `max_over_time()`, or directly
   - **Histogram**: Buckets of observations with cumulative counts
     - Examples: `http_request_duration_seconds_bucket`, `response_size_bytes_bucket`
     - Use with: `histogram_quantile()`, `rate()`
   - **Summary**: Pre-calculated quantiles with count and sum
     - Examples: `rpc_duration_seconds{quantile="0.95"}`
     - Use `_sum` and `_count` for averages; don't average quantiles

3. **Label Discovery**: What labels are available on these metrics?
   - Common labels: `job`, `instance`, `environment`, `service`, `endpoint`, `status_code`, `method`
   - Ask which labels are important for filtering or grouping

Use the **AskUserQuestion** tool to confirm metric names, types, and available labels.

### Stage 3: Determine Query Parameters

Gather specific requirements for the query.

#### Pre-confirmation for User-Provided Parameters

**IMPORTANT**: When the user has already specified parameters in their initial request (e.g., "5-minute window", "500ms threshold", "> 5% error rate"), you MUST:

1. **Acknowledge the provided values** explicitly in your response
2. **Present them as pre-filled defaults** in AskUserQuestion with the first option being "Use specified values"
3. **Allow quick confirmation** rather than re-asking for information already given

**Example**: If user says "alert when P95 latency exceeds 500ms", use:
```
AskUserQuestion:
- Question: "Confirm the alert threshold?"
- Options:
  1. "500ms (as specified)" - Use the threshold from your request
  2. "Different threshold" - Let me specify a different value
```

This respects the user's input and speeds up the workflow while still allowing modifications.

1. **Time Range**: What time window should the query cover?
   - Instant value (current)
   - Rate over time (`[5m]`, `[1h]`, `[1d]`)
   - For rate calculations: typically `[1m]` to `[5m]` for real-time, `[1h]` to `[1d]` for trends
   - Rule of thumb: Rate range should be at least 4x the scrape interval

2. **Label Filtering**: Which labels should filter the data?
   - Exact matches: `job="api-server"`, `status_code="200"`
   - Negative matches: `status_code!="200"`
   - Regex matches: `instance=~"prod-.*"`
   - Multiple conditions: `{job="api", environment="production"}`

3. **Aggregation**: Should the data be aggregated?
   - **No aggregation**: Return all time series as-is
   - **Aggregate by labels**: `sum by (job, endpoint)`, `avg by (instance)`
   - **Aggregate without labels**: `sum without (instance, pod)`, `avg without (job)`
   - Common aggregations: `sum`, `avg`, `max`, `min`, `count`, `topk`, `bottomk`

4. **Thresholds or Conditions**: Are there specific conditions?
   - For alerting: threshold values (e.g., error rate > 5%)
   - For filtering: only show series above/below a value
   - For comparison: compare against historical data (offset)

Use the **AskUserQuestion** tool to gather or confirm these parameters. When the user has already provided values (e.g., "5-minute window", "> 5%"), present them as the default option for confirmation.

### Stage 4: Present the Query Plan

**BEFORE GENERATING ANY CODE**, present a plain-English query plan and ask for user confirmation:

```
## PromQL Query Plan

Based on your requirements, here's what the query will do:

**Goal**: [Describe the monitoring goal in plain English]

**Query Structure**:
1. Start with metric: `[metric_name]`
2. Filter by labels: `{label1="value1", label2="value2"}`
3. Apply function: `[function_name]([metric][time_range])`
4. Aggregate: `[aggregation] by ([label_list])`
5. Additional operations: [any calculations, ratios, or transformations]

**Expected Output**:
- Data type: [instant vector/scalar]
- Labels in result: [list of labels]
- Value represents: [what the number means]
- Typical range: [expected value range]

**Example Interpretation**:
If the query returns `0.05`, it means: [plain English explanation]

**Does this match your intentions?**
- If yes, I'll generate the query and validate it
- If no, let me know what needs to change
```

Use the **AskUserQuestion** tool to confirm the plan with options:
- "Yes, generate this query"
- "Modify [specific aspect]"
- "Show me alternative approaches"

When the user chooses:
- **"Modify [specific aspect]"**: ask one focused follow-up question about what to change (metric, labels, function, time range, threshold, or output shape), then present an updated plan before generating.
- **"Show me alternative approaches"**: provide at least two valid query plans with trade-offs (accuracy, cost, cardinality, readability), then ask the user to choose one before generating.

### Stage 5: Generate the PromQL Query

Once the user confirms the plan, generate the actual PromQL query following best practices.

#### IMPORTANT: Consult Reference Files Before Generating

**Before writing any query code**, you MUST:

1. **Identify the query category** first (histogram, RED, USE, function-specific, optimization, etc.).

2. **Read only the relevant reference section(s)** using the Read tool:
   - For histogram queries → Read `references/metric_types.md` (Histogram section)
   - For error/latency patterns → Read `references/promql_patterns.md` (RED method section)
   - For resource monitoring → Read `references/promql_patterns.md` (USE method section)
   - For optimization questions → Read `references/best_practices.md`
   - For specific functions → Read `references/promql_functions.md`
   - Re-read a section only if requirements changed or you have not consulted it yet in the current thread.

3. **If a needed reference cannot be read**, state the issue and continue with best-effort generation using the most applicable documented pattern you already have.

4. **Cite the applicable pattern or best practice** in your response:
   ```
   As documented in references/promql_patterns.md (Pattern 3: Latency Percentile):
   # 95th percentile latency
   histogram_quantile(0.95, sum by (le) (rate(...)))
   ```

5. **Reference example files** when generating similar queries:
   ```
   Based on examples/red_method.promql (lines 64-82):
   # P95 latency with proper histogram_quantile usage
   ```

This keeps generated queries aligned with documented patterns while avoiding unnecessary full-file rereads on iterative follow-ups.

#### Best Practices for Query Generation

1. **Always Use Label Filters**
   ```promql
   # Good: Specific filtering reduces cardinality
   rate(http_requests_total{job="api-server", environment="prod"}[5m])

   # Bad: Matches all time series, high cardinality
   rate(http_requests_total[5m])
   ```

2. **Use Appropriate Functions for Metric Types**
   ```promql
   # Counter: Use rate() or increase()
   rate(http_requests_total[5m])

   # Gauge: Use directly or with *_over_time()
   memory_usage_bytes
   avg_over_time(memory_usage_bytes[5m])

   # Histogram: Use histogram_quantile()
   histogram_quantile(0.95,
     sum by (le) (rate(http_request_duration_seconds_bucket[5m]))
   )
   ```

3. **Apply Aggregations with by() or without()**
   ```promql
   # Aggregate by specific labels (keeps only these labels)
   sum by (job, endpoint) (rate(http_requests_total[5m]))

   # Aggregate without specific labels (removes these labels)
   sum without (instance, pod) (rate(http_requests_total[5m]))
   ```

4. **Use Exact Matches Over Regex When Possible**
   ```promql
   # Good: Faster exact match
   http_requests_total{status_code="200"}

   # Bad: Slower regex match when not needed
   http_requests_total{status_code=~"200"}
   ```

5. **Calculate Ratios Properly**
   ```promql
   # Error rate: errors / total requests
   sum(rate(http_requests_total{status_code=~"5.."}[5m]))
   /
   sum(rate(http_requests_total[5m]))
   ```

6. **Use Recording Rules for Complex Queries**
   - If a query is used frequently or is computationally expensive
   - Pre-aggregate data to reduce query load
   - Follow naming convention: `level:metric:operations`

7. **Format for Readability**
   ```promql
   # Good: Multi-line for complex queries
   histogram_quantile(0.95,
     sum by (le, job) (
       rate(http_request_duration_seconds_bucket{job="api-server"}[5m])
     )
   )
   ```

#### Common Query Patterns

**Pattern 1: Request Rate**
```promql
# Requests per second
rate(http_requests_total{job="api-server"}[5m])

# Total requests per second across all instances
sum(rate(http_requests_total{job="api-server"}[5m]))
```

**Pattern 2: Error Rate**
```promql
# Error ratio (0 to 1)
sum(rate(http_requests_total{job="api-server", status_code=~"5.."}[5m]))
/
sum(rate(http_requests_total{job="api-server"}[5m]))

# Error percentage (0 to 100)
(
  sum(rate(http_requests_total{job="api-server", status_code=~"5.."}[5m]))
  /
  sum(rate(http_requests_total{job="api-server"}[5m]))
) * 100
```

**Pattern 3: Latency Percentile (Histogram)**
```promql
# 95th percentile latency
histogram_quantile(0.95,
  sum by (le) (
    rate(http_request_duration_seconds_bucket{job="api-server"}[5m])
  )
)
```

**Pattern 4: Resource Usage**
```promql
# Current memory usage
process_resident_memory_bytes{job="api-server"}

# Average CPU usage over 5 minutes
avg_over_time(process_cpu_seconds_total{job="api-server"}[5m])
```

**Pattern 5: Availability**
```promql
# Percentage of up instances
(
  count(up{job="api-server"} == 1)
  /
  count(up{job="api-server"})
) * 100
```

**Pattern 6: Saturation/Queue Depth**
```promql
# Average queue length
avg_over_time(queue_depth{job="worker"}[5m])

# Maximum queue depth in the last hour
max_over_time(queue_depth{job="worker"}[1h])
```

### Stage 6: Validate the Generated Query

**ALWAYS attempt to validate the generated query first** using the devops-skills:promql-validator skill:

```
After generating the query, automatically invoke:
Skill(devops-skills:promql-validator)

The devops-skills:promql-validator skill will:
1. Check syntax correctness
2. Validate semantic logic (correct functions for metric types)
3. Identify anti-patterns and inefficiencies
4. Suggest optimizations
5. Explain what the query does
6. Verify it matches user intent
```

**Validation checklist**:
- Syntax is correct (balanced brackets, valid operators)
- Metric type matches function usage
- Label filters are specific enough
- Aggregation is appropriate
- Time ranges are reasonable
- No known anti-patterns
- Query is optimized for performance

If validation fails, fix issues and re-validate until all checks pass.

If the validator skill is unavailable, fails to run, or cannot complete after two fix/re-validate cycles:
- Report the validator failure briefly (tool unavailable, timeout, parsing error, etc.).
- Run a manual fallback check (syntax shape, metric/function compatibility, label filtering, aggregation, time range sanity).
- Mark any unchecked areas as **UNVERIFIED** and ask the user whether to proceed with best-effort output or provide more context for another validation attempt.

**IMPORTANT: Display Validation Results to User**

After running validation, you MUST display the structured results to the user in this format:

```
## PromQL Validation Results

### Syntax Check
- Status: ✅ VALID / ⚠️ WARNING / ❌ ERROR / ⚠️ UNVERIFIED
- Issues: [list any syntax errors]

### Best Practices Check
- Status: ✅ OPTIMIZED / ⚠️ CAN BE IMPROVED / ❌ HAS ISSUES / ⚠️ UNVERIFIED
- Issues: [list any problems found]
- Suggestions: [list optimization opportunities]

### Validation Coverage
- Validator tool run: [successful / failed / unavailable]
- Checks completed: [syntax, semantics, anti-patterns, performance, intent-match]
- Checks skipped: [list any skipped checks, or "None"]

### Query Explanation
- **What it measures**: [plain English description]
- **Output labels**: [list labels in result, or "None (scalar)"]
- **Expected result structure**: [instant vector / scalar / etc.]
```

This transparency helps users understand the validation process and any recommendations.

### Stage 7: Provide Usage Instructions

After generation and validation (or manual fallback validation), provide the user with:

1. **The Final Query**:
   ```promql
   [Generated and validated PromQL query]
   ```

2. **Query Explanation**:
   - What the query measures
   - How to interpret the results
   - Expected value range
   - Labels in the output

3. **How to Use It**:
   - **For Dashboards**: Copy into Grafana/Prometheus UI panel query
   - **For Alerts**: Integrate into Alertmanager rule with threshold
   - **For Recording Rules**: Add to Prometheus recording rule config
   - **For Ad-hoc**: Run directly in Prometheus expression browser

4. **Customization Notes**:
   - Time ranges that might need adjustment
   - Labels to modify for different environments
   - Threshold values to tune
   - Alternative functions if requirements change

5. **Related Queries**:
   - Suggest complementary queries
   - Mention recording rule opportunities
   - Recommend dashboard panels

## Native Histograms (Prometheus 3.x+)

Native histograms are now **stable** in Prometheus 3.0+ (released November 2024). They offer significant advantages over classic histograms:
- Sparse bucket representation with near-zero cost for empty buckets
- No configuration of bucket boundaries during instrumentation
- Coverage of the full float64 range
- Efficient mergeability across histograms
- Simpler query syntax

> **Important**: Starting with Prometheus v3.8.0, native histograms are fully stable. However, scraping native histograms still requires explicit activation via the `scrape_native_histograms` configuration setting. Starting with v3.9, no feature flag is needed but `scrape_native_histograms` must be set explicitly.

### Native vs Classic Histogram Syntax

```promql
# Classic histogram (requires _bucket suffix and le label)
histogram_quantile(0.95,
  sum by (job, le) (rate(http_request_duration_seconds_bucket[5m]))
)

# Native histogram (simpler - no _bucket suffix, no le label needed)
histogram_quantile(0.95,
  sum by (job) (rate(http_request_duration_seconds[5m]))
)
```

### Native Histogram Functions

```promql
# Get observation count rate from native histogram
histogram_count(rate(http_request_duration_seconds[5m]))

# Get sum of observations from native histogram
histogram_sum(rate(http_request_duration_seconds[5m]))

# Calculate fraction of observations between two values
histogram_fraction(0, 0.1, rate(http_request_duration_seconds[5m]))

# Average request duration from native histogram
histogram_sum(rate(http_request_duration_seconds[5m]))
/
histogram_count(rate(http_request_duration_seconds[5m]))
```

### Detecting Native vs Classic Histograms

Native histograms are identified by:
- **No `_bucket` suffix** on the metric name
- **No `le` label** in the time series
- The metric stores histogram data directly (not separate bucket counters)

When querying, check if your Prometheus instance has native histograms enabled:
```yaml
# prometheus.yml - Enable native histogram scraping
scrape_configs:
  - job_name: 'my-app'
    scrape_native_histogram: true  # Prometheus 3.x+
```

### Custom Bucket Native Histograms (NHCB)

Prometheus 3.4+ supports custom bucket native histograms (schema -53), allowing classic histogram to native histogram conversion. This is a key migration path for users with existing classic histograms.

**Benefits of NHCB**:
- Keep existing instrumentation (no code changes needed)
- Store classic histograms as native histograms for lower costs
- Query with native histogram syntax
- Improved reliability and compression

**Configuration** (Prometheus 3.4+):
```yaml
# prometheus.yml - Convert classic histograms to NHCB on scrape
global:
  scrape_configs:
    - job_name: 'my-app'
      convert_classic_histograms_to_nhcb: true  # Prometheus 3.4+
```

**Querying NHCB**:
```promql
# Query NHCB metrics the same way as native histograms
histogram_quantile(0.95, sum by (job) (rate(http_request_duration_seconds[5m])))

# histogram_fraction also works with NHCB (Prometheus 3.4+)
histogram_fraction(0, 0.2, rate(http_request_duration_seconds[5m]))
```

**Note**: Schema -53 indicates custom bucket boundaries. These histograms with different custom bucket boundaries are generally not mergeable with each other.

---

## SLO, Error Budget, and Burn Rate Patterns

Service Level Objectives (SLOs) are critical for modern SRE practices. These patterns help implement SLO-based monitoring and alerting.

### Error Budget Calculation

```promql
# Error budget remaining (for 99.9% SLO over 30 days)
# Returns value between 0 and 1 (1 = full budget, 0 = exhausted)
1 - (
  sum(rate(http_requests_total{job="api", status_code=~"5.."}[30d]))
  /
  sum(rate(http_requests_total{job="api"}[30d]))
) / 0.001  # 0.001 = 1 - 0.999 (allowed error rate)

# Simplified: Availability over 30 days
sum(rate(http_requests_total{job="api", status_code!~"5.."}[30d]))
/
sum(rate(http_requests_total{job="api"}[30d]))
```

### Burn Rate Calculation

Burn rate measures how fast you're consuming error budget. A burn rate of 1 means you'll exhaust the budget exactly at the end of the SLO window.

```promql
# Current burn rate (1 hour window, 99.9% SLO)
# Burn rate = (current error rate) / (allowed error rate)
(
  sum(rate(http_requests_total{job="api", status_code=~"5.."}[1h]))
  /
  sum(rate(http_requests_total{job="api"}[1h]))
) / 0.001  # 0.001 = allowed error rate for 99.9% SLO

# Burn rate > 1 means consuming budget faster than allowed
# Burn rate of 14.4 consumes 2% of monthly budget in 1 hour
```

### Multi-Window, Multi-Burn-Rate Alerts (Google SRE Standard)

The recommended approach for SLO alerting uses multiple windows to balance detection speed and precision:

```promql
# Page-level alert: 2% budget in 1 hour (burn rate 14.4)
# Long window (1h) AND short window (5m) must both exceed threshold
(
  (
    sum(rate(http_requests_total{job="api", status_code=~"5.."}[1h]))
    /
    sum(rate(http_requests_total{job="api"}[1h]))
  ) > 14.4 * 0.001
)
and
(
  (
    sum(rate(http_requests_total{job="api", status_code=~"5.."}[5m]))
    /
    sum(rate(http_requests_total{job="api"}[5m]))
  ) > 14.4 * 0.001
)

# Ticket-level alert: 5% budget in 6 hours (burn rate 6)
(
  (
    sum(rate(http_requests_total{job="api", status_code=~"5.."}[6h]))
    /
    sum(rate(http_requests_total{job="api"}[6h]))
  ) > 6 * 0.001
)
and
(
  (
    sum(rate(http_requests_total{job="api", status_code=~"5.."}[30m]))
    /
    sum(rate(http_requests_total{job="api"}[30m]))
  ) > 6 * 0.001
)
```

### SLO Recording Rules

Pre-compute SLO metrics for efficient alerting:

```yaml
# Recording rules for SLO calculations
groups:
  - name: slo_recording_rules
    interval: 30s
    rules:
      # Error ratio over different windows
      - record: job:slo_errors_per_request:ratio_rate1h
        expr: |
          sum by (job) (rate(http_requests_total{status_code=~"5.."}[1h]))
          /
          sum by (job) (rate(http_requests_total[1h]))

      - record: job:slo_errors_per_request:ratio_rate5m
        expr: |
          sum by (job) (rate(http_requests_total{status_code=~"5.."}[5m]))
          /
          sum by (job) (rate(http_requests_total[5m]))

      # Availability (success ratio)
      - record: job:slo_availability:ratio_rate1h
        expr: |
          1 - job:slo_errors_per_request:ratio_rate1h
```

### Latency SLO Queries

```promql
# Percentage of requests faster than SLO target (200ms)
(
  sum(rate(http_request_duration_seconds_bucket{le="0.2", job="api"}[5m]))
  /
  sum(rate(http_request_duration_seconds_count{job="api"}[5m]))
) * 100

# Requests violating latency SLO (slower than 500ms)
(
  sum(rate(http_request_duration_seconds_count{job="api"}[5m]))
  -
  sum(rate(http_request_duration_seconds_bucket{le="0.5", job="api"}[5m]))
)
/
sum(rate(http_request_duration_seconds_count{job="api"}[5m]))
```

### Burn Rate Reference Table

| Burn Rate | Budget Consumed | Time to Exhaust 30-day Budget | Alert Severity |
|-----------|-----------------|-------------------------------|----------------|
| 1         | 100% over 30d   | 30 days                       | None           |
| 2         | 100% over 15d   | 15 days                       | Low            |
| 6         | 5% in 6h        | 5 days                        | Ticket         |
| 14.4      | 2% in 1h        | ~2 days                       | Page           |
| 36        | 5% in 1h        | ~20 hours                     | Page (urgent)  |

---

## Advanced Query Techniques

### Using Subqueries

Subqueries enable complex time-based calculations:

```promql
# Maximum 5-minute rate over the past 30 minutes
max_over_time(
  rate(http_requests_total[5m])[30m:1m]
)
```

**Syntax**: `<query>[<range>:<resolution>]`
- `<range>`: Time window to evaluate over
- `<resolution>`: Step size between evaluations

### Using Offset Modifier

Compare current data with historical data:

```promql
# Compare current rate with rate from 1 week ago
rate(http_requests_total[5m])
-
rate(http_requests_total[5m] offset 1w)
```

### Using @ Modifier

Query metrics at specific timestamps:

```promql
# Rate at the end of the range query
rate(http_requests_total[5m] @ end())

# Rate at specific Unix timestamp
rate(http_requests_total[5m] @ 1609459200)
```

### Binary Operators and Vector Matching

Combine metrics with operators and control label matching:

```promql
# One-to-one matching (default)
metric_a + metric_b

# Many-to-one with group_left
rate(http_requests_total[5m])
* on (job, instance) group_left (version)
  app_version_info

# Ignoring specific labels
metric_a + ignoring(instance) metric_b
```

### Logical Operators

Filter time series based on conditions:

```promql
# Return series only where value > 100
http_requests_total > 100

# Return series present in both
metric_a and metric_b

# Return series in A but not in B
metric_a unless metric_b
```

## Documentation Lookup

If the user asks about specific Prometheus features, operators, or custom metrics:

1. **Try context7 MCP first (preferred)**:
   ```
   Use mcp__context7__resolve-library-id with "prometheus"
   Then use mcp__context7__get-library-docs with:
   - context7CompatibleLibraryID: /prometheus/docs
   - topic: [specific feature, function, or operator]
   - page: 1 (fetch additional pages if needed)
   ```

2. **Fallback to WebSearch**:
   ```
   Search query pattern:
   "Prometheus PromQL [function/operator/feature] documentation [version] examples"

   Examples:
   "Prometheus PromQL rate function documentation examples"
   "Prometheus PromQL histogram_quantile documentation best practices"
   "Prometheus PromQL aggregation operators documentation"
   ```

## Common Monitoring Scenarios

### RED Method (for Request-Driven Services)

1. **Rate**: Request throughput
   ```promql
   sum(rate(http_requests_total{job="api"}[5m])) by (endpoint)
   ```

2. **Errors**: Error rate
   ```promql
   sum(rate(http_requests_total{job="api", status_code=~"5.."}[5m]))
   /
   sum(rate(http_requests_total{job="api"}[5m]))
   ```

3. **Duration**: Latency percentiles
   ```promql
   histogram_quantile(0.95,
     sum by (le) (rate(http_request_duration_seconds_bucket{job="api"}[5m]))
   )
   ```

### USE Method (for Resources)

1. **Utilization**: Resource usage percentage
   ```promql
   (
     avg(rate(node_cpu_seconds_total{mode!="idle"}[5m]))
     /
     count(node_cpu_seconds_total{mode="idle"})
   ) * 100
   ```

2. **Saturation**: Queue depth or resource contention
   ```promql
   avg_over_time(node_load1[5m])
   ```

3. **Errors**: Error counters
   ```promql
   rate(node_network_receive_errs_total[5m])
   ```

## Alerting Rules

When generating queries for alerting:

1. **Include the Threshold**: Make the condition explicit
   ```promql
   # Alert when error rate exceeds 5%
   (
     sum(rate(http_requests_total{status_code=~"5.."}[5m]))
     /
     sum(rate(http_requests_total[5m]))
   ) > 0.05
   ```

2. **Use Boolean Operators**: Return 1 (fire) or 0 (no alert)
   ```promql
   # Returns 1 when memory usage > 90%
   (process_resident_memory_bytes / node_memory_MemTotal_bytes) > 0.9
   ```

3. **Consider for Duration**: Alerts typically use `for` clause
   ```yaml
   alert: HighErrorRate
   expr: |
     (
       sum(rate(http_requests_total{status_code=~"5.."}[5m]))
       /
       sum(rate(http_requests_total[5m]))
     ) > 0.05
   for: 10m  # Only fire after 10 minutes of continuous violation
   ```

## Recording Rules

When generating queries for recording rules:

1. **Follow Naming Convention**: `level:metric:operations`
   ```yaml
   # level: aggregation level (job, instance, etc.)
   # metric: base metric name
   # operations: functions applied

   - record: job:http_requests:rate5m
     expr: sum by (job) (rate(http_requests_total[5m]))
   ```

2. **Pre-aggregate Expensive Queries**:
   ```yaml
   # Recording rule for frequently-used latency query
   - record: job_endpoint:http_request_duration_seconds:p95
     expr: |
       histogram_quantile(0.95,
         sum by (job, endpoint, le) (
           rate(http_request_duration_seconds_bucket[5m])
         )
       )
   ```

3. **Use Recorded Metrics in Dashboards**:
   ```promql
   # Instead of expensive query, use pre-recorded metric
   job_endpoint:http_request_duration_seconds:p95{job="api-server"}
   ```

## Error Handling

### Common Issues and Solutions

1. **Empty Results**:
   - Check if metrics exist: `up{job="your-job"}`
   - Verify label filters are correct
   - Check time range is appropriate
   - Confirm metric is being scraped

2. **Too Many Series (High Cardinality)**:
   - Add more specific label filters
   - Use aggregation to reduce series count
   - Consider using recording rules
   - Check for label explosion (dynamic labels)

3. **Incorrect Values**:
   - Verify metric type (counter vs gauge)
   - Check function usage (rate on counters, not gauges)
   - Verify time range is appropriate
   - Check for counter resets

4. **Performance Issues**:
   - Reduce time range for range vectors
   - Add label filters to reduce cardinality
   - Use recording rules for complex queries
   - Avoid expensive regex patterns
   - Consider query timeout settings

## Communication Guidelines

When generating queries:

1. **Explain the Plan**: Always present a plain-English plan before generating
2. **Ask Questions**: Use AskUserQuestion tool to gather req...