Apache Airflow MCP Server

Fetch task instance logs with optional filtering and truncation.

Large log handling: Logs >100MB automatically tail to last 10,000 lines (sets auto_tailed=true). Host-segmented responses are flattened into a single string using headers of the form --- [worker] ---, ensuring agents can reason about multi-host output. The tool requires an explicit try_number; callers should first retrieve it via airflow_get_task_instance.

Filter order of operations:

1. Auto-tail: If log >100MB, take last 10,000 lines

2. tail_lines: Extract last N lines from log

3. filter_level: Find matching lines by level (content filter)

4. context_lines: Add surrounding lines around matches (symmetric: N before + N after)

5. max_bytes: Hard cap on total output (UTF-8 safe truncation)

Parameters

• instance: Instance key (optional, mutually exclusive with ui_url)

• ui_url: Airflow UI URL to resolve identifiers (optional)

• dag_id, dag_run_id, task_id, try_number: Task instance identifiers (required)

• filter_level: "error" | "warning" | "info" (optional) - Show only lines matching level

  • "error": ERROR, CRITICAL, FATAL, Exception, Traceback

  • "warning": WARN, WARNING + error patterns

  • "info": INFO + warning + error patterns

• context_lines: N lines before/after each match (optional, clamped to [0, 1000]; accepts int/float/str, coerced to non-negative int, fractional values truncated)

• tail_lines: Extract last N lines before filtering (optional, clamped to [0, 100000]; accepts int/float/str, coerced to non-negative int, fractional values truncated)

• max_bytes: Maximum response size in bytes (default: 100KB ≈ 25K tokens, clamped to reasonable limit)

Returns

• Response dict with fields:

  • log: Normalized/filtered log text (host headers inserted when needed)

  • truncated: true if output exceeded max_bytes

  • auto_tailed: true if original log >100MB triggered auto-tail

  • bytes_returned: Actual byte size of returned log

  • original_lines: Line count before any filtering

  • returned_lines: Line count after all filtering/truncation

  • match_count: Number of lines matching filter_level (before context expansion)

  • meta.try_number: Attempt number for this task instance

  • meta.filters: Echo of effective filters applied (shows clamped values)

  • ui_url: Direct link to log view in Airflow UI

  • request_id: Correlates with server logs

• Raises: ToolError with compact JSON payload (code, message, request_id, optional context)