Kafka MCP

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list_clusters

Lists Kafka clusters available to this server, showing reachability, read-only status, and whether the session can write. Use it to find valid destinations for producing or copying messages.

Instructions

List the Kafka clusters this server serves, with whether each is reachable, whether it is configured read_only, and whether this session may write to it (writable). Connectivity is checked at call time. A cluster is a valid copy_message or produce_message destination_cluster only when writable is true. Broker and credential details are not exposed.

Input Schema

Name	Required	Description	Default
No arguments

Output Schema

Name	Required	Description	Default
`count`	Yes
`clusters`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.2.7Oct 25, 2026

addedOutput schema / properties / clusters / items / properties / writable
```
Added value: +{
+  "type": "boolean"
+}
```

changedOutput schema / properties / clusters / items / required

Previous value: -[
-  "name",
-  "connected",
-  "read_only"
-]New value: +[
+  "name",
+  "connected",
+  "read_only",
+  "writable"
+]

First observedv0.2.0Oct 7, 2026

TDQS

A4.4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does well: it discloses that connectivity is checked at call time (a live probe, not cached data) and that broker and credential details are deliberately withheld, which is a meaningful security/data-exposure boundary. It doesn't cover call failure modes or whether the result is ordered, keeping it from a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with what is listed, then the field semantics, then the gating rule and the disclosure boundary. Every sentence adds distinct information and none restates the name or title.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so the description needn't re-explain return values, and with zero parameters the surface is small. It covers the field meanings, the liveness caveat, and the credential-exposure guard; only edge behavior (e.g., what a session-scoped writable=false implies for retries) is left implicit.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so the baseline of 4 applies; there are no argument semantics that could be under-specified. The description correctly implies a no-argument, whole-server listing.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('List the Kafka clusters this server serves') and enumerates the per-cluster attributes returned (reachable, read_only, writable). It is clearly distinguishable from sibling tools like cluster_health, list_topics, and server_config, which handle health metrics, topics, and server configuration respectively.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a concrete downstream usage rule: a cluster is only a valid copy_message or produce_message destination_cluster when writable is true, which tells the agent exactly why and when to call this first. It stops short of explicitly excluding alternatives (e.g., when to prefer cluster_health instead), so it lands at 4 rather than 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.