posthog-mcp-server

list_cohorts

List all PostHog cohorts in a project, showing name, type, person count, and creation date. Optionally filter by search query and limit results.

Instructions

List all PostHog cohorts in the project. Shows name, type, person count, and creation date.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_cohorts"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No	Max cohorts to return (default 100)
`search`	No	Search query to filter cohorts by name

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 6, 2026

TDQS

B3.4/5.0

Behavior2/5

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

No annotations are provided, so the description must carry the full burden. It says 'List all' but doesn't mention the default limit of 100, pagination, or other behavioral aspects. The output fields are specified, but key behavioral details are missing, making 'all' potentially misleading.

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

Conciseness4/5

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

The description is a single, clear sentence that front-loads the purpose and key output details. It is appropriately concise, though it could have included a note about the limit behavior without becoming verbose.

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

Completeness3/5

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

For a simple list tool, the description covers the return fields and purpose, but it omits the default limit behavior and fails to mention that 'all' is constrained by the limit parameter. This gap makes the description somewhat incomplete given no annotations or output schema.

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

Parameters3/5

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

The input schema has 100% coverage with descriptions for both parameters (limit and search), so the description adds no additional meaning. Baseline 3 is appropriate since the schema does the heavy lifting.

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?

The description clearly states the action ('List') and the resource ('all PostHog cohorts'), plus the fields shown. This distinguishes it from sibling tools like list_events and list_persons, which target different resources.

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

Usage Guidelines3/5

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

The description implies this tool is for listing cohorts, but gives no explicit guidance on when to use it versus alternatives. There are no exclusions or named sibling alternatives, so it relies on the implicit resource name.

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

Deploy Server