Honest comparison — each tool below is great at what it's built for. MCPSpend is the one that natively understands the MCP tool call as the unit of work. If you primarily care about LLM-layer tokens or general product analytics, you may be better served elsewhere — links below.
LLM observability
Helicone is great at tracking the chat-completion layer (input/output tokens per OpenAI/Anthropic call). It does not see MCP tool calls — agents that wrap a single chat turn around 50 tool invocations look identical to a single chat turn.
Use Helicone when: You want pure LLM-layer cost: tokens in/out per provider model.
LLM tracing & evals
Langfuse traces LLM calls, prompt versions, and offline evaluations. Strong on dev-time observability. To capture MCP tool calls you have to instrument every server yourself with their SDK.
Use Langfuse when: You want full traces + evals + are willing to add SDK calls inside every MCP server you maintain.
Product analytics
PostHog is a powerful general analytics platform. It can model anything if you push the right events — including MCP tool calls — but it has no built-in concept of "tool / server / cost", so you build the whole schema yourself.
Use PostHog when: You already run PostHog and want one less vendor — accepting that you'll wire the cost model by hand.
AI gateway
Portkey is an AI gateway that sits in front of LLM providers — caching, routing, fallback, guardrails. It tracks cost at the LLM-request level. MCP tool calls only show up if you have already wired Portkey into your stack and instrumented every call.
Use Portkey when: You want a smart routing/caching layer between your code and OpenAI/Anthropic — accepting that MCP tool attribution is on you.
Open-source LLM analytics
Lunary is an open-source LLM monitoring + prompt management tool. Strong on user-feedback loops, prompt versioning, and evals. To see MCP tool calls you have to instrument each server with their SDK — out of the box it tracks LLM completions, not MCP tools.
Use Lunary when: You want a self-hostable observability stack focused on LLM prompts + evals + user feedback.
Generic API analytics
APIAnalytics is a general-purpose API monitoring tool — request volume, latency, status codes. It can technically count MCP requests if you put it in front of your transport, but it has no model, no cost concept, and no awareness of the MCP tool layer.
Use APIAnalytics when: You want bare-metal HTTP/API metrics for any service — including but not limited to MCP.