diff --git a/docs/vrs/01-ding/requirements.md b/docs/vrs/01-ding/requirements.md
index 130f72fa..3fe9a55d 100644
--- a/docs/vrs/01-ding/requirements.md
+++ b/docs/vrs/01-ding/requirements.md
@@ -20,10 +20,10 @@ is in [`spec.md`](./spec.md).
 
 ## Assumptions
 
-- **DING-A01 Rendered screens only:** The only available evidence about a
-  composer's state is a rendered terminal screen. No maintained harness exposes
-  an evented idle signal, so every precondition below is a measured heuristic
-  over text. `DQ2` in [`../spec.md`](../spec.md) tracks closing that gap.
+`DING-A01 Rendered screens only` is retired. Rendered-screen evidence is a
+limit of the legacy `ding` transport. It is not an assumption for a maintained
+harness that declares a native `deliver` transport.
+
 - **DING-A02 Cooperative human:** The human sharing a pane is not adversarial.
   A screen that deliberately imitates another harness's composer is a
   correctness concern, not a security boundary, consistent with `A02`.
@@ -41,21 +41,43 @@ is in [`spec.md`](./spec.md).
 
 ## Requirements
 
-### Must preserve initial transport and gate every retry
-
-- **DING-R01 Combined initial transport:** A fresh notice uses one bounded PTY
-  transaction containing the bracketed paste, the accepted 0.5 second delay,
-  and Return. Ownership is recorded before that command starts. Composer
-  heuristics do not split or suppress this initial transport.
-- **DING-R02 Two adjacent retained-safe retry observations:** A later bare
-  Return is permitted only for a transport-owned payload whose exact notice is
-  still the complete composer and is classified `RetainedSafe` in two
-  immediately adjacent inspections. The final observation is adjacent to the
-  Return itself. Any change, block, or uncertainty prevents retry submission.
-- **DING-R03 Fail-closed receipt and retry:** After the initial transport, a
-  changed composer, a human draft, an active turn, a modal, an unreadable
-  screen, an unrecognized harness, and a bounded observation timeout never
-  become `Delivered` and receive no retry input. Anything not positively
+### Must select one explicit transport
+
+- **DING-R11 Declared transport:** An agent selects at most one delivery
+  transport. `ding` selects the legacy screen transport. `deliver "mcp"`
+  selects the Claude native transport. `deliver "app-server"` selects the
+  Codex native transport. A declaration with neither node has no DING delivery.
+  A declaration with both nodes, multiple `deliver` nodes, or an unsupported
+  `deliver` value is invalid.
+- **DING-R12 No transport inference:** st2 does not infer a native transport
+  from an agent command or a screen. Native delivery uses the declared adapter.
+  A binary that supports `deliver` validates its value and its mutual exclusion
+  with `ding`.
+- **DING-R13 Durable native delivery:** The inbox file remains the source of
+  truth for native delivery. Only the adapter's declared success condition can
+  complete a delivery attempt. A closed, unavailable, stale, or unknown native
+  transport leaves the message unread and retryable. Archive precedence and
+  restart recovery remain unchanged.
+- **DING-R14 Missing transport report:** Doctor reports an active agent that
+  declares neither `ding` nor `deliver`. The omission remains a valid opt-out
+  and does not block the agent. The report makes a no-delivery state visible.
+
+### Must preserve legacy transport and gate every legacy retry
+
+- **DING-R01 Combined initial transport:** A fresh legacy notice uses one
+  bounded PTY transaction containing the bracketed paste, the accepted 0.5
+  second delay, and Return. Ownership is recorded before that command starts.
+  Composer heuristics do not split or suppress this initial transport.
+- **DING-R02 Two adjacent retained-safe retry observations:** A later legacy
+  bare Return is permitted only for a transport-owned payload whose exact
+  notice is still the complete composer and is classified `RetainedSafe` in
+  two immediately adjacent inspections. The final observation is adjacent to
+  the Return itself. Any change, block, or uncertainty prevents retry
+  submission.
+- **DING-R03 Fail-closed receipt and retry:** After the initial legacy
+  transport, a changed composer, a human draft, an active turn, a modal, an
+  unreadable screen, an unrecognized harness, and a bounded observation timeout
+  never become `Delivered` and receive no retry input. Anything not positively
   understood retains staged ownership. On an inspect-only staged retry, a
   maintained adapter may positively prove that the exact owned payload is no
   longer retained; that proof relinquishes ownership only when an archive
diff --git a/docs/vrs/01-ding/spec.md b/docs/vrs/01-ding/spec.md
index 3d432022..65b114d1 100644
--- a/docs/vrs/01-ding/spec.md
+++ b/docs/vrs/01-ding/spec.md
@@ -10,6 +10,42 @@ specified in [`01-claude/spec.md`](./01-claude/spec.md) and
 Active. A map to the implementation and its evidence, not a replacement for the
 tests.
 
+## Delivery selection
+
+Delivery is opt-in. An agent declaration selects one transport:
+
+| Declaration | Transport |
+| --- | --- |
+| `ding` | Legacy screen transport |
+| `deliver "mcp"` | Claude native MCP transport |
+| `deliver "app-server"` | Codex native app-server transport |
+| Neither node | No delivery |
+
+`ding` and `deliver` are mutually exclusive. More than one `deliver` node is
+invalid. Any other `deliver` value is invalid. st2 does not infer a transport
+from the agent command because command arguments are opaque.
+
+The native selector is a new `deliver` node. A binary released before this
+contract ignores that unknown agent child. It lowers a valid `deliver`-only
+agent with no delivery sidecar. The agent receives no DING. It does not silently
+use the legacy screen transport. This is a visible delivery outage.
+
+A binary that supports `deliver` validates its value and its mutual exclusion
+with `ding`. Native delivery must not be encoded as an argument to `ding`,
+because a pre-change parser would accept that form as legacy `ding` and use the
+wrong transport. Doctor reports an active agent that declares no transport. The
+report does not make the valid no-delivery opt-out an error.
+
+The durable inbox is the source of truth for every transport. An archive with
+the same message name wins. A native adapter completes delivery only after its
+declared provider-specific success condition. If the adapter is closed,
+unavailable, stale, or in an unknown state, it sends no unsafe input and leaves
+the inbox message unread for retry. Native adapters do not use the
+rendered-screen classifier.
+
+The rest of this document defines the unchanged legacy screen transport. The
+native wire contracts are in each maintained harness specification.
+
 ## Composer states
 
 One inspection of a rendered screen, evaluated against one exact expected
@@ -45,11 +81,11 @@ staged retry ─► receipt ─┬─ Accepted ───────────
                          └─ RetainedBlocked / Unproven ─────────────► Staged
 ```
 
-Fresh delivery preserves the production transport: one bounded PTY transaction
-contains a bracketed paste, a 0.5 second delay, and Return (`DING-R01`).
-Ownership is recorded immediately before that transaction. The production path
-does not inspect the composer first and does not use the separate staging
-helper.
+Fresh legacy delivery preserves the production transport: one bounded PTY
+transaction contains a bracketed paste, a 0.5 second delay, and Return
+(`DING-R01`). Ownership is recorded immediately before that transaction. The
+production path does not inspect the composer first and does not use the
+separate staging helper.
 
 Every failure of that terminal command or of the following receipt observation
 resolves to `Staged` (`DING-R07`): the paste and Return may already have reached
@@ -148,10 +184,11 @@ Declared `busy` never suppresses delivery; only fresh `dnd` defers it
 
 ## Known limits
 
-- Idle proof depends on footer chrome that a harness may render differently
-  across permission or approval modes. A harness whose footer is not recognized
-  in a given mode defers indefinitely rather than delivering. This is an
-  explicit limit per `T01`, and each harness spec states which modes it proves.
-- The classifier is a measured heuristic over rendered text, not an evented
-  signal, so a renderer change can defer delivery until the grammar is updated.
-  Tracked as `DQ2` in [`../spec.md`](../spec.md).
+- Legacy idle proof depends on footer chrome that a harness may render
+  differently across permission or approval modes. A harness whose footer is
+  not recognized in a given mode defers indefinitely rather than delivering.
+  This is an explicit limit per `T01`, and each harness spec states which modes
+  it proves.
+- The legacy classifier is a measured heuristic over rendered text, not an
+  evented signal, so a renderer change can defer legacy delivery until the
+  grammar is updated. Maintained native transports do not use this classifier.
diff --git a/docs/vrs/02-agent-spec/spec.md b/docs/vrs/02-agent-spec/spec.md
index 5ef2aedb..e7b524d3 100644
--- a/docs/vrs/02-agent-spec/spec.md
+++ b/docs/vrs/02-agent-spec/spec.md
@@ -358,10 +358,13 @@ Authoring: [pinned complete declaration][evals-fields]. st2 source:
 
 <h3 id="f14">F14 Compact agent fields</h3>
 
-Compact `command`, `argv`, `env`, `lifecycle`, and `ding` convert to the
-generated agent PTY and derived sidecar. The tasks use F09, F11, and F12;
-`ding` carries the dependency on the generated agent task described there.
-Compact syntax adds no other behavior.
+Compact `command`, `argv`, `env`, and `lifecycle` define the generated agent
+PTY. Bare `ding` selects the derived legacy screen sidecar. `deliver "mcp"`
+selects native Claude delivery. `deliver "app-server"` selects native Codex
+delivery. The two selector nodes are mutually exclusive. More than one
+`deliver` node and any other value are invalid. Neither node means no delivery.
+Each generated transport depends on the generated agent task. The tasks use
+F09, F11, and F12. Compact syntax adds no other behavior.
 
 Authoring: [pinned compact tasks][evals-tasks]. That document and st2 `9887b28`
 predate compact `argv` and `lifecycle`. Current st2 source:
@@ -370,9 +373,10 @@ predate compact `argv` and `lifecycle`. Current st2 source:
 
 <h3 id="f15">F15 Provider and ignored fields</h3>
 
-Core st2 ignores `harness`, `model`, `persona`, `permissions`, `transport`,
-`strategy`, `meta`, and provider extensions. They do not change core equality,
-wake behavior, or actions. Providers may convert them into F05 through F14;
+Core st2 ignores `harness`, `model`, `persona`, `permissions`, the legacy
+render-only `transport` field, `strategy`, `meta`, and provider extensions.
+They do not change core equality, wake behavior, or actions. Providers may
+convert them into F05 through F14;
 core acts only on that concrete output.
 
 Authoring: [pinned complete declaration][evals-fields]. st2 source:
diff --git a/docs/vrs/ontology.md b/docs/vrs/ontology.md
index 38606fb0..e57b46cb 100644
--- a/docs/vrs/ontology.md
+++ b/docs/vrs/ontology.md
@@ -154,9 +154,12 @@ Authority: [`message::Message`](../../src/message.rs#L26-L46)
 
 ### DING
 
-The terminal notification that makes an agent aware of unread messages.
+The delivery signal that makes an agent aware of unread messages. A declaration
+selects either the legacy terminal transport or one provider-native control
+transport.
 
-Authority: [DING module contract](../../src/ding/mod.rs#L1-L14)
+Authority: [DING specification](./01-ding/spec.md) and
+[DING module contract](../../src/ding/mod.rs#L1-L14)
 
 ## Collision rules
 
@@ -172,7 +175,7 @@ Authority: [DING module contract](../../src/ding/mod.rs#L1-L14)
   value and [bus ID](../../crates/agent-spec/src/spec.rs#L203-L211) for the
   host-qualified address.
 - Use [message](../../src/message.rs#L26-L46) for the durable record and
-  [DING](../../src/ding/mod.rs#L1-L14) for its terminal notification.
+  [DING](./01-ding/spec.md) for its delivery signal.
 
 ## Avoid
 
diff --git a/docs/vrs/requirements.md b/docs/vrs/requirements.md
index dc519e72..18bd6ab9 100644
--- a/docs/vrs/requirements.md
+++ b/docs/vrs/requirements.md
@@ -84,7 +84,10 @@ accepted.
 - **R05 DING/archive semantics:** Inbox delivery, archive precedence, retries,
   suppression, and restart recovery are deterministic and tested. DING may
   interrupt agent work, but it must not alter or submit a human's active draft;
-  an unknown interaction state defers delivery.
+  an unknown interaction state defers delivery. A declaration selects either
+  the legacy screen transport or one supported native transport. st2 does not
+  infer a native transport from an opaque command. A failed or unavailable
+  transport leaves the inbox message unread and retryable.
 - **R06 Restartable launch definitions:** A restarted PTY or exec receives the
   complete effective launch definition, including environment and supported
   launch fields.
diff --git a/docs/vrs/spec.md b/docs/vrs/spec.md
index 561aa7ce..a894f073 100644
--- a/docs/vrs/spec.md
+++ b/docs/vrs/spec.md
@@ -664,6 +664,34 @@ atomic inbox file → DING attempt → agent reads → archive receipt
   composer cannot create a short-lived PTY probe on every inbox poll. Inbox
   reads do not wake the sidecar; only mutations bypass its bounded poll cadence.
 
+### Declared native DING delivery (DQ2 resolution)
+
+An agent selects at most one delivery transport. `ding` keeps the legacy
+screen transport unchanged. `deliver "mcp"` selects native Claude delivery.
+`deliver "app-server"` selects native Codex delivery. An agent with neither
+node has no delivery. The two node forms are mutually exclusive, multiple
+`deliver` nodes are invalid, and an unknown `deliver` value is invalid.
+
+The transport is explicit because an agent command is opaque. A binary released
+before this contract ignores the unknown `deliver` child. It lowers a valid
+`deliver`-only declaration with no delivery sidecar. The agent receives no DING
+instead of receiving a DING through the legacy screen transport. This is a
+visible delivery outage. A binary that supports `deliver` validates its value
+and its mutual exclusion with `ding`.
+
+Native delivery is not an argument to `ding`, which a pre-change parser would
+accept as legacy delivery and route through the wrong transport. Doctor reports
+an active agent that declares neither transport. The no-delivery form remains a
+valid opt-out and does not block the agent.
+
+Native delivery replaces rendered-screen inference for maintained Claude and
+Codex agents that select it. Each native adapter uses its provider's evented
+control channel and its provider-specific success condition. A closed,
+unavailable, stale, or unknown channel sends no unsafe input. The durable inbox
+message remains unread and retryable. Archive precedence, suppression, and
+restart recovery remain the same for every transport. The legacy classifier
+remains available only for agents that select `ding`.
+
 ## State and scope
 
 - **R08:** Presence and activity status are separate signals. The catalog must
@@ -785,15 +813,6 @@ the resident supervisor continues to reconcile the complete local catalog.
   boundary, and execution receipts are not yet specified. A successful
   executable eval and Nathan's approval should resolve this before adding
   scheduler requirements.
-- **DQ2 Safe DING delivery:** Bounded observation now replaces the fixed
-  paste-to-Return delay: maintained Codex and Claude composers must be
-  positively empty before paste and show the exact staged notice twice before
-  a separate Return. Human, modal, active, changed, timed-out, and unknown
-  states fail closed, with staged-payload ownership preventing duplicate paste.
-  This measured screen heuristic is still not an evented proof and renderer
-  changes may defer delivery. Resolve the remaining gap with a stronger evented
-  signal or other measured classifier; a small on-device model is an optional
-  experiment, not a required architecture.
 - **DQ3 Catalog agent state:** Define the catalog paths, schemas, freshness
   rules, and atomic update semantics for presence, activity status, current
   plan, and current plan step. Prove that stale state is distinguishable and