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Documentation Index

Fetch the complete documentation index at: https://agenticadvertisingorg-changeset-release-main.mintlify.app/llms.txt

Use this file to discover all available pages before exploring further.

L3 enforces what AdCP means on the agent side. The wire shape is well-formed (L0); the caller is authentic (L1) and authorized (L2); now: is the request legal given the current state of the world? For agents, L3 is the bulk of the protocol surface — the 3–4 person-month from-scratch build lives almost entirely here. For callers, L3 is consumer-side: weeks of handler glue, classifying error codes and handling state transitions rather than enforcing them.

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What an SDK at L3 must provide

If you’re picking an SDK or porting one to a new language, this is the L3 build target:
  • Lifecycle state-machine graphs for all spec-defined resources, with a transition-assertion primitive that emits the spec-correct error code (NOT_CANCELLABLE / INVALID_STATE / etc.).
  • Idempotency cache with cross-payload conflict detection and the no-payload-echo invariant on IDEMPOTENCY_CONFLICT envelopes.
  • Async-task store + dispatcher — tools opt into async; the SDK returns task_id, accepts polling, and emits the terminal artifact.
  • Webhook emitter — signed, retried, idempotent.
  • The conformance test surface (comply_test_controller), wired to drive state deterministically when the resolved account is in sandbox or mock mode (and rejected otherwise).
  • Per-resource persistence primitives that handle the spec’s echo contracts.
  • Server-construction entry point that ties all of the above together with sane defaults.
For the cumulative cross-layer story (what L0+L1+L2+L3 buys you), see the SDK stack reference. For what changed at L3 between 2.5 and 3.0, see What changed at L3 in 3.0.

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