posthog-mcp-server

list_experiments

Retrieve all PostHog A/B tests with their status and key results to evaluate experiment performance and make data-driven decisions.

Instructions

List all PostHog experiments (A/B tests) in the project. Shows name, status, and key results.

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_experiments"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No	Max experiments to return (default 50)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 6, 2026

TDQS

A3.6/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden. It mentions that it shows 'name, status, and key results' but fails to disclose that the 'all' is subject to a limit parameter (default 50), which could mislead users expecting truly all results. It also omits pagination or other behavioral details.

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?

The description is two sentences, front-loaded with the primary purpose and followed by a brief mention of returned fields. Every word earns its place, with no redundancy or fluff.

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 with one optional parameter and no output schema, the description is mostly adequate. It states purpose and output fields, but misses the critical detail about the limit behavior and does not explain how to retrieve a specific experiment (though sibling naming implies it). The 'all' vs 'limit' discrepancy is a notable gap.

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

Parameters2/5

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

The schema fully documents the 'limit' parameter, so coverage is 100%. However, the description's use of 'List all' directly conflicts with the parameter's purpose of capping results, and the description adds no additional meaning beyond the schema. The contradiction undermines clarity.

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 'List all PostHog experiments (A/B tests)' with a specific verb and resource, and the scope is 'in the project'. It distinguishes from sibling tools like get_experiment (which likely retrieves a single experiment) and list_events (a different resource). The purpose is unambiguous.

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?

The description gives clear context: this tool is for listing all experiments. It does not explicitly name alternatives or exclusions, but the phrase 'all experiments' implies when to use it versus get_experiment for a single experiment. No misleading guidance is present.

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

Deploy Server