footprintjs
open source · MIT

The self-explaining stack.

From backend pipelines to AI agents — every run records why it did what it did. Trace any answer back to the exact cause, and prove the fix by replaying it.

Why it's one ecosystem

Every run records itself as it happens — not reconstructed from logs afterward. One trustworthy trace, and you choose the lens.

1 Collect at traversal time Reads, writes, and decisions are captured structurally as the run executes — no manual logging.
2 One canonical footprint The trace is the execution record — built inline, never rebuilt after the fact.
3 You choose the lens Metrics, narrative, visualization, agent debugging — every tool composes on the same record.
Inline recording is truth. Post-processing is reconstruction.
the ecosystem · as its own footprint graph

footprintjs

core engine

The flowchart pattern for backend code — causal traces, transactional state, and auto-generated tool descriptions. Everything else is built on this.

agentfootprint

agentic framework

Build AI agents whose every LLM call traces back to what was injected, who triggered it, when, and how it cached. Context engineering, abstracted. Built on footprintjs.

Explainable UI

for footprintjs

Visualize a footprintjs run — the flowchart, the causal trace, and the data at every step. Themeable React components.

Lens

for agentfootprint

Debug an agentfootprint run — messages, prompts, tool calls, decision scope, and cost. Built on Explainable UI.

Thinking UI

role replay

The non-developer's view of an agent run — its reasoning and tool loop replayed as an animated, scrubbable story, so anyone can see what it did and where it went wrong. No build step.