Glossary

The vocabulary of MCP analytics.

Plain definitions grounded in the real product: MCP sessions, tool call success rate, adoption, clients and returning users, followed by earlier agent observability terms.

14 terms
Definition

MCP session

An MCP session is the group of tool calls that belong to one attempted job, from the first call to how the job ended.

It is not the same as a network connection or transport session: the MCP 2026-07-28 specification removed protocol-level sessions from its stateless core. Flowlines uses supplied session context when available and labels sessions it infers, which can split related work or group separate requests.

Can I see a full MCP session? ›
Definition

MCP tool call success rate

MCP tool call success rate is the share of tool calls with a known result that completed without an error, measured over a fixed window.

Divide successful calls by calls with a known result and report unknown results separately. In a synthetic example, 348 successful calls out of 360 is a 96.7% call success rate. A successful call does not prove the user's job was done, so read it next to session outcomes.

What is my tool call success rate? ›
Definition

MCP adoption

MCP adoption is the number of distinct users outside your own team who call an MCP server in a period, and the share of them who keep using it.

Call volume is not adoption: one script can generate hundreds of calls. Count distinct users and sessions, exclude internal and test traffic, and read the result with identity coverage and the returning share.

Is anyone using my MCP server? ›
Definition

Returning MCP user

A returning MCP user is someone active on an MCP server in the selected period who was also active in an earlier period.

Returning users divided by active users gives the returning share, the clearest early sign that a server became part of someone's workflow. It needs a stable, permitted user identifier; anonymous calls cannot be counted as returning.

How many users come back? ›
Definition

MCP client

An MCP client is the component inside an AI application, such as Claude, ChatGPT or Cursor, that connects to an MCP server and calls its tools.

In MCP analytics, the client is usually the application name reported with each request. It is self-reported and identifies the application, not the person, so recognizing one user across clients needs a stable user identifier. Keep calls without a client name in an unknown group.

Which AI clients call my server? ›
Definition

MCP journey

An MCP journey is the reconstructed path from a user's use case through the MCP tools an agent called to the resulting outcome.

Flowlines shows calls per session, repeated-call loops, failed sessions, and typical tool paths for each intent cluster. It distinguishes a technically successful call from a journey that actually helped the user.

See MCP observability ›
Definition

Outcome coverage

Outcome coverage is the share of observed MCP activity for which Flowlines has enough context to connect tool execution to a user outcome.

A successful tool status does not prove that the agent completed the task. Outcome coverage makes that gap visible and helps teams find where additional context is needed to judge success.

See MCP journey evidence ›
Definition

Trace ingestion

Trace ingestion is how production sessions enter Flowlines through OpenTelemetry push, read-only Langfuse or LangSmith polling, or a one-time public LangSmith trace import.

The standard live path accepts OTLP/JSON or protobuf at the Flowlines traces endpoint and routes data using a namespace API key. Provider connectors can poll existing traces without replacing the source trace store.

How do I connect Flowlines to my agent? ›
Definition

Behavioral observability

Behavioral observability is the practice of measuring how an AI agent behaves across many sessions and users, not just whether individual calls succeeded.

Where execution observability inspects one LLM call, behavioral observability looks across sessions: which issues recur, who is affected, what users intended, and which original sessions show the pattern. It turns trace data into operating answers.

How do I know if my agent is working in production? ›
Definition

Behavior issue

A behavior issue is a recurring agent pattern such as looping, drifting, user frustration, abandonment, poor result quality, hallucination, or a safety problem.

Flowlines separates behavior issues from reliability errors. Each issue includes what happened, why it matters, the next step, technical detection details, where it fires, and the affected production sessions.

What signals does Flowlines detect out of the box? ›
Definition

Behavioral cohort

A behavioral cohort is a group of users summarized by what they did in observed agent sessions rather than by demographic attributes.

The Flowlines Home view includes user cohorts alongside active users, intents, issues, and sessions that need attention. Cohort context helps teams see whether a recurring issue is broad or concentrated among a particular group of users.

How do I segment my users by behavior? ›
Definition

Issue-free rate

Issue-free rate is the share of analyzed chats without a detected behavior issue or reliability error in the selected period.

It appears on the Flowlines Home view next to analyzed chats, active users, and negative feedback. It gives operators a fast health read while the Issues and Search views provide the evidence behind the aggregate.

How do I know if my agent is working in production? ›
Definition

Evidence session

An evidence session is a production conversation or agent run linked directly to a detected issue so a team can verify the finding in context.

Issue details in Flowlines connect the summary and next step to the exact sessions where the pattern occurred. This keeps a conclusion inspectable and gives engineering a concrete starting point for diagnosis.

How do I find the failure modes my logs don't show? ›
Definition

Agent drift

Agent drift is the gradual divergence of an agent's behavior from its original instructions, learned state, or expected outcomes over time.

Drift often does not crash. It appears as a behavior issue that recurs across sessions, users, intents, or tool journeys. The useful unit of investigation is the pattern plus the original sessions, not an isolated response.

How do I detect agent drift over time? ›

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