Elasticsearch Logs

Elasticsearch Logs

Read-only log search over an Elasticsearch cluster you already run. NetClaw installs no cluster and indexes nothing — this queries what is already there.

Server: elasticsearch-mcp (adopted, docker.elastic.co/mcp/elasticsearch, Apache-2.0, digest-pinned) · 5 tools · 1,094 tokens

The rule that matters most

A bare search total is capped at 10,000 and reads as if it were exact.

Elasticsearch stops counting at 10,000 and marks the total relation: "gte" — meaning at least. This server discards that qualifier and prints Total results: 10000. There is nothing in the response to tell you the number is a floor.

Measured against 10,075 real documents:

On a million-document index a bare search still says 10,000. The error is unbounded and invisible.

Therefore, for any question of the form "how many", "how often", "which is most", or any number a human will act on:

1. Use esql with STATS COUNT(*), or
2. Use search with "track_total_hits": true in the query_body.

search without that guard is for retrieving example documents only — never for counting. If you report a total that came from an unguarded search, you are reporting a number that may be arbitrarily wrong.

Tools

Note the argument names are snake_case (query_body, index_pattern). Wrong names fail loudly with a deserialization error — they are not silently ignored.

Worked patterns

How many errors, by device — a counting question, so ESQL:

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esql: FROM netclaw-syslog | WHERE severity == "error" | STATS n = COUNT(*) BY device | SORT n DESC

Show me examples of those errors — a retrieval question, so search:

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search: index=netclaw-syslog
        query_body={"query":{"term":{"severity":"error"}}, "size":20, "track_total_hits":true}

What am I even working with — always start here on an unfamiliar cluster:

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list_indices: index_pattern=*
get_mappings: index=<the one you picked>

Guessing field names is the most common cause of a query that returns nothing. A term query against a text field, or an aggregation on one, will not behave as expected — check the mapping first. Fields are commonly foo (analysed text) plus foo.keyword (exact); use .keyword for grouping, sorting, and exact matches.

Empty is not the same as zero

A query returning no hits means this query found nothing. It does not establish that the event did not occur. Before reporting "no errors", confirm:

• the index actually holds data for the time range (list_indices doc counts, or an ESQL count with no filter)
• the field names came from get_mappings, not from a guess
• the time range matches how the data is actually timestamped

Say "no matching events in <index> for <range>" — not "no errors occurred".

Boundaries — which backend answers

NetClaw has several log and metric backends. Pick by where the data lives, not by question shape:

If you do not know where the logs live, ask. Do not query every backend hoping one answers — an empty result from the wrong store is indistinguishable from an absence of events.

Read-only

All five tools read. There is no index, update, delete, or reindex verb in the manifest, so no write is reachable regardless of the credential. Prefer an Elasticsearch API key with read/view_index_metadata only — the server will happily use a superuser credential, and nothing in it needs one.

Configuration

Upstream status

This server is deprecated by Elastic and receives critical security updates only. It was adopted deliberately: its replacement, Agent Builder's MCP endpoint, is Enterprise-tier on self-managed, so the supported path is paywalled while this one is Apache-2.0, already published, and works against a free Basic cluster. The image is digest-pinned so a security-only update cannot change answers underneath you. See specs/096-elastic-logs/spec.md.