Inspect

Query the API server to explore stored conversations. The /v1/* surface splits into two views: sessions — one row per harness/agent session, UUID-keyed — and stems — the Merkle leaf-chain, forensic view, hash-keyed. A stem is a single root-to-leaf path through the Merkle DAG; earlier versions of the API called a leaf path a “session.”

System

GET /ping Health check endpoint

GET /metrics Prometheus RED metrics (unauthenticated)

GET /v1/stats Aggregate counts, tokens, cost, duration, tool calls

Sessions

The product session view, backed by the sessions table populated by the session-tracking ingest path.

GET /v1/sessions One harness/agent session per row, newest-first, cursor-paginated (?limit, ?cursor)

GET /v1/sessions/:id A session plus the selected stem of turns and a summary of every stem in it (?stem=longest|all, ?root=<hash>)

Stems

The Merkle leaf-chain, forensic view. Filterable by project, agent_name, model, provider, since, and until.

GET /v1/stems Per-leaf-chain aggregates: cost, tokens, status, duration

GET /v1/stems/:hash A leaf’s ancestry chain, root-first (supports ?depth=N)

GET /v1/stems/:hash/graph Graph-shaped DAG projection for visualization

Search & agents

GET /v1/search Semantic search across stored sessions (requires embeddings)

ALL /v1/mcp MCP server for agent integration (requires embeddings)

API server runs on port 8081 by default when using tapes serve. The /metrics endpoint is intentionally unauthenticated so an in-cluster Prometheus can scrape it — see tapes serve metrics. For MCP endpoint details, see MCP API Reference.

Migrating from the older API

The leaf-chain endpoints moved under /v1/stems so /v1/sessions could become the product session view. Response shapes for the moved endpoints are unchanged.

Before	After
`GET /v1/sessions` (leaf-node list)	`GET /v1/sessions` now returns one row per harness/agent session; the leaf list is removed
`GET /v1/sessions/summary`	`GET /v1/stems`
`GET /v1/sessions/:hash`	`GET /v1/stems/:hash`
`GET /v1/sessions/:hash/graph`	`GET /v1/stems/:hash/graph`
—	`GET /v1/sessions/:id` (new)

OpenAPI Spec

The API server ships its own generated reference. With tapes serve running:

GET /swagger Interactive Scalar UI rendered from the OpenAPI spec

GET /swagger/doc.json OpenAPI 3 spec (JSON) — feed it to your client codegen of choice

Open http://localhost:8081/swagger in a browser for the live reference.

DAG visualization web UI

The API server ships an optional browser UI that renders the Merkle DAG of a session — useful for stepping through conversation turns visually. It is off by default; enable it explicitly so an unintentionally exposed API server doesn't serve a UI.

# Standalone API server
tapes serve api --web-ui --postgres "$DSN"

# All-in-one
tapes serve --api-web-ui --postgres "$DSN"

With the flag set, the API server serves the UI at / and exposes a graph-shaped projection of each stem at:

GET /v1/stems/:hash/graph

The graph endpoint returns nodes and edges suitable for client-side rendering. It's the same data the bundled web UI reads, so you can build your own front end against it.