Kubesense Logs

KubeSense Logs

Requires the KubeSense MCP server; see kubesense-mcp for connection, auth, and the shared WHERE-clause reference. Tools here resolve RBAC against the logs module.

Tools

Reading rows to compute a total is the most common mistake. If the question is "how many", "how often", or "which is worst", use analyze-logs — one call over the whole window beats paginating raw rows, and is more accurate.

Field Names — Catalog Labels Only

The server rejects storage column names at every input slot (where, required_fields, group_by_fields, fields, sort_by) with:

field "pod_name" is a storage column; use the catalog label "instance" instead

That is the complete set of 13 fields get-trace-or-log-fields advertises for logs. Three more parse but are hidden from discovery: timestamp, pattern_id, body_length.

[!WARNING] There is no service field on logs. service exists only on traces (→ app_service). service = checkout against logs returns unknown field "service" for signal=logs. Use workload for the application name.

node on logs, node_name on traces. The two signals disagree — logs use node (→ host), traces use node_name. Carrying a field name across signals is a predictable failure.

Enum values are UPPERCASE on logs

type accepts exactly: ERROR, WARN, INFO, DEBUG, TRACE, FATAL, PANIC. Casing is significant — type = error matches nothing.

(Traces use lowercase status = error. The two signals differ in both the field name and the casing.)

format accepts json, klog, nginx — lowercase.

[!NOTE] Read casing off the enum_values column of get-trace-or-log-fields, not the example column. The example generator misses several enum fields (including type) and returns a blank cell for them. enum_values is always correct.

WHERE Syntax

type = ERROR AND namespace = production
type IN (ERROR, FATAL) AND workload = checkout
NOT (env_type = dev)
body ILIKE "%timeout%"
@user.id = abc-123

Operators the WHERE parser actually accepts: = != < > <= >= LIKE ILIKE SUBSTR_ILIKE IN, combined with AND / OR / NOT and parentheses.

[!WARNING] The operators column of get-trace-or-log-fields over-advertises. HAS_TOKEN, HAS_ALL, HAS_ANY, LIKE_AND, ILIKE_LOG, IS_IP_ADDRESS appear in the legend but have no WHERE-string syntax — body HAS_TOKEN oom fails to parse. Stick to the list above.

Quoting. Bare values may contain only letters, digits, _, ., -. Anything with a slash, colon, %, or space must be double-quoted:

body ILIKE "%connection refused%"      ✓
timestamp > "2026-07-30T10:00:00Z"     ✓
body ILIKE %timeout%                   ✗ parse error

NOT IN does not parse as a leaf. Write NOT (namespace IN (kube-system, default)).

Attributes carry an @ prefix in WHERE and work correctly on logs:

@user.id = abc-123
@http.status_code > 400

Attribute operators: = != IN < > <= >= LIKE ILIKE. Unquoted numeric attribute values are coerced to numbers, so @latency > 100 compares numerically.

[!WARNING] exist(@field) is broken on both signals — it emits an EXIST operator carrying a value, which the validator rejects (operator "EXIST" takes no values (got 1)). There is no working existence check. Filter on a concrete value instead.

In group_by_fields / fields / required_fields / sort_by there is no @ — set the flag instead:

{ "field": "user.id", "is_attribute": true }

search-logs

{
  "from_time": "2026-07-30T10:00:00Z",
  "to_time": "2026-07-30T11:00:00Z",
  "where": "type = ERROR AND namespace = production",
  "required_fields": [
    { "field": "instance", "is_attribute": false },
    { "field": "body", "is_attribute": false }
  ],
  "page_size": 50
}

Output is TSV: a # total_count=<N> error_count=<N> is_free_search=<bool> line, a header row, then one row per log. total_count is for the whole window, ignoring page_size — compare it to the rows you received to know whether more exist.

Pagination is window-based

There is no page or offset parameter. The window is half-open (from_time <= timestamp < to_time), so you page by narrowing to_time:

1. Query your real window.
2. Take the minimum timestamp among the returned rows — do not assume the last row is the oldest.
3. Call again with the same from_time and where, and to_time = that minimum, copied verbatim.
4. Stop when a call returns fewer rows than page_size, or the answer is settled.

Timestamps are RFC3339 UTC with millisecond precision. Copy the cell exactly — truncating to whole seconds re-reads or skips rows within that second.

[!IMPORTANT] A paged scan is a sample, not a census. Rows are ordered toStartOfHour(timestamp) DESC, cluster DESC, timestamp DESC — hour-bucket first, then cluster. When one hour holds more matching rows than page_size across several clusters, advancing to_time can skip rows in a cluster the scan hadn't reached. To read exhaustively, pin clusters to a single cluster and use a large page_size. Otherwise prefer a bigger page_size over more pages, and analyze-logs over pagination for anything aggregate.

is_free_search

Touching body, trace_id, span_id, or any attribute routes the query to the raw table instead of the pre-aggregated rollups — slower, but the only way to see message text. It is computed automatically and reported in the output header. Column-only filters stay on the fast rollup path.

analyze-logs

{
  "from_time": "2026-07-30T10:00:00Z",
  "to_time": "2026-07-30T11:00:00Z",
  "query_type": "range",
  "where": "type = ERROR",
  "group_by_fields": [ { "field": "workload", "is_attribute": false } ],
  "value_operation": "row_count",
  "sort_direction": "DESC",
  "limit": 10
}

• query_type: range for a time series, instant for one number per series.
• value_operation: row_count, unique_count, avg, sum, min, max, p50, p90, p95, p99.
• fields supplies the operand for everything except row_count: unique_count of pods → value_operation: "unique_count", fields: [{"field": "instance"}].
• limit caps series on range queries (top-N by max value, default 20); ignored for instant.

[!WARNING] value_operation: "count" is not valid — the correct name is row_count. The tool schema's own summary line says "Common: count, avg, …", which is wrong.

body cannot be used in group_by_fields (it doesn't exist on the rollup tables). It is a filter-only field. Group by pattern_id if you want to cluster similar messages.

Output shape

Columnar JSON keyed by query label ("A"). For range, a single shared timestamps array (Unix seconds) is emitted once and each series carries a positionally-aligned values array (null = no data in that bucket). For instant, each series carries one scalar value. total_series/truncated report how many non-zero series existed before the top-N cap.

Worked Examples

Error count per workload, last hour, as a trend query_type: range, where: "type = ERROR", group_by_fields: [{"field":"workload"}], value_operation: row_count

How many distinct pods logged a fatal error right now query_type: instant, where: "type = FATAL", value_operation: unique_count, fields: [{"field":"instance"}]

Read the actual timeout messages search-logs, where: 'body ILIKE "%timeout%" AND workload = checkout', required_fields: [{"field":"instance"},{"field":"body"}], page_size: 50

Error rate as a percentage — needs two queries plus a formula, so use analyze-telemetry; see kubesense-mcp.

Rules

1. Call get-trace-or-log-fields with signal: "logs" first, passing the same window you will query — attribute keys are window-scoped.
2. Use catalog labels: type, instance, container, node. Never level, pod_name, container_name, host.
3. There is no service field on logs — use workload.
4. type values are UPPERCASE (ERROR, not error). Read casing from enum_values, never from example.
5. Quote any value containing /, :, %, or a space.
6. NOT (x IN (...)), not x NOT IN (...).
7. Stick to = != < > <= >= LIKE ILIKE SUBSTR_ILIKE IN — the advertised token/index operators have no WHERE syntax.
8. value_operation is row_count, not count.
9. analyze-logs for counts and trends; search-logs only to read messages. Never paginate to compute an aggregate.
10. Page by narrowing to_time to the minimum timestamp returned; there is no offset. Treat multi-cluster paged scans as samples unless you pin one cluster.
11. body is filter-only — it cannot be a group-by.