diff --git a/AGENT-SPEC.md b/AGENT-SPEC.md
index 366f526e..a6d15d50 100644
--- a/AGENT-SPEC.md
+++ b/AGENT-SPEC.md
@@ -44,6 +44,8 @@ owns product work. Shipped declarations must not contain a developer's absolute
 ```kdl
 agent "<identity>" {
   identity "<identity>"
+  name "<human-facing name>"
+  description "<enduring responsibility>"
   host "<host>"
   role "worker"
   type "service"
@@ -83,6 +85,8 @@ Supported agent children are:
 | Node | Meaning |
 |---|---|
 | `identity "…"` | Overrides the positional/path-derived identity. |
+| `name "…"` | Optional, non-unique human-facing name. It never routes or selects work. |
+| `description "…"` | Optional enduring responsibility boundary. It never grants authority. |
 | `host "…"` | Execution host. The canonical folder path and content should agree. |
 | `role "…"` | Optional metadata with no execution behavior. |
 | `type "service"` | Optional; `service` is the only accepted value and the default. |
@@ -103,6 +107,51 @@ Canonical declarations normally omit `type`. Unknown non-render children may be
 extension syntax, and required behavior must never depend on them. `schedule` is explicitly reserved and
 rejected. Unknown render directives are errors.
 
+## Stable identity and presentation
+
+The positional or child `identity` remains the stable automation ID. It alone
+owns bus routing, supervisor edges, task IDs, durable state paths, resources,
+authorization, and lifecycle reconciliation. Existing positional and child
+identity grammar remains valid; roster JSON continues to expose the stable bus
+ID as `identity`.
+
+`name` and `description` are optional presentation metadata. Explicit values
+must be non-empty, trimmed, single-line, and free of control characters. Limits
+are 160 Unicode scalars for `name` and 1,000 for `description`; omission means
+absent. Names need not be unique and are never st2 message, status, resource,
+authorization, or lifecycle aliases. The retired sibling `name` file is not a
+fallback source.
+
+The roster exposes separate nullable `name` and `description` fields. Mutable
+canonical KDL can be edited source-preservingly with:
+
+```console
+st2 rename <stable-id> <name>
+st2 rename <stable-id> --clear
+st2 describe <stable-id> <description>
+st2 describe <stable-id> --clear
+```
+
+An agent may edit itself; a declared supervisor ancestor may edit a descendant;
+an operator with no `ST_AGENT` may edit a selected mutable catalog. Peer edits
+fail. JSON, TOML, and declarations marked `meta { managed-by "nix" }` are
+readable but refuse these live authoring commands. Concurrent commands serialize
+through the catalog lock and preserve both accepted field edits.
+
+Every managed PTY receives the owned tags
+`agent.presentation.schema=1`, `agent.actor.path=<host>.<identity>`, and the
+optional `agent.presentation.description`. Only the primary `agent` PTY maps
+Agent Spec `name` to native `displayName`; secondary PTYs retain their existing
+task-specific display behavior. st2 reconciles this envelope through exact PTY
+IDs with one atomic metadata patch, preserves unrelated tags, clears removed
+owned fields, emits one coherent `metadata_change` event per real transition,
+and emits no event for a no-op. Presentation reconciliation never replaces the
+PTY process or its durable Agent Spec state.
+
+This contract is proved model-free by
+[`agent-presentation-contract`](./cells/agent-presentation-contract/) and
+[`agent-presentation-continuity`](./cells/agent-presentation-continuity/).
+
 The restart defaults are 3 attempts per 60 seconds, no delay, and `mode "delay"`. Durations accept bare
 seconds or `ms`, `s|sec|secs`, `m|min|mins`, `h|hr|hrs`, and `d|day|days`. `mode "delay"` keeps retrying with
 the window reset; `mode "fail"` parks the task after attempts are exhausted and sends one best-effort
diff --git a/CATALOG.md b/CATALOG.md
index 233e7a66..36bec7f6 100644
--- a/CATALOG.md
+++ b/CATALOG.md
@@ -1,7 +1,7 @@
 <!-- Generated by bin/generate-catalog.sh from cell KDL and evidence/*.tsv. Do not edit. -->
 # Current eval catalog and evidence
 
-This is the sole current corpus surface: **58 included cells** (18 model-free,
+This is the sole current corpus surface: **60 included cells** (20 model-free,
 40 model-backed) and **4 retired exclusions**. Inventory fields are derived from the active
 KDL and executable judge scripts. Latest accepted PASS evidence remains distinct from the append-only run
 history: a failed last run is visible without being advertised as accepted evidence, and cells with no
@@ -17,6 +17,8 @@ harness-native loader plus canonical hook file.
 | Cell | Harness | Model(s) / effort | Model seats | Cost | Timeout | Held-out judges | Latest accepted PASS | Last recorded run |
 |---|---|---|---:|---|---|---:|---|---|
 | `adopt-only-migration` | model-free | — | 0 | none | `90s` | 6 | — | **NO STRUCTURED RUN** |
+| `agent-presentation-continuity` | model-free | — | 0 | none | `90s` | 5 | — | **NO STRUCTURED RUN** |
+| `agent-presentation-contract` | model-free | — | 0 | none | `90s` | 8 | — | **NO STRUCTURED RUN** |
 | `agent-spec-resource-bindings` | model-free | — | 0 | none | `60s` | 4 | — | **NO STRUCTURED RUN** |
 | `assignment-contract-cold-assignment` | Codex | `gpt-5.6-sol` / medium | 2 | medium | `1200s` | 3 | — | **NO STRUCTURED RUN** |
 | `assignment-contract-cold-focus` | Codex | `gpt-5.6-sol` / medium | 2 | medium | `1200s` | 3 | — | **NO STRUCTURED RUN** |
@@ -95,6 +97,8 @@ while the last-run column makes a recorded failure distinct from a cell with no
 ## Harness hook exclusions
 
 - `adopt-only-migration` / `cell` — deterministic native adoption/replacement lifecycle probe; no harness seat
+- `agent-presentation-continuity` / `cell` — deterministic native presentation continuity probe; no harness seat
+- `agent-presentation-contract` / `cell` — deterministic native Agent Spec and PTY presentation probe; no harness seat
 - `agent-spec-resource-bindings` / `cell` — deterministic native Agent Spec Resource-envelope probe; no harness seat
 - `context-resource-continuity` / `cell` — deterministic native context/resource restart probe; no harness seat
 - `docs` / `judge:cold-reader` — one-shot offline Claude print grader; no bus identity, DING, or hook surface
@@ -114,7 +118,7 @@ while the last-run column makes a recorded failure distinct from a cell with no
 - `targeted-reconcile-isolation` / `cell` — deterministic selected reconcile isolation probe; no bus-connected agent
 - `two-networks-coexist` / `cell` — deterministic catalog-isolation probe; no harness seat
 
-These **19** rows are generated from structured exclusions. A cell-level row is required for
+These **21** rows are generated from structured exclusions. A cell-level row is required for
 every derived model-free cell. The one-shot docs cold reader is a model-backed grader, but not a bus-connected
 agent: it has no st2 identity, DING sidecar, or lifecycle hooks.
 
diff --git a/cells/agent-presentation-continuity/README.md b/cells/agent-presentation-continuity/README.md
new file mode 100644
index 00000000..1d1f279e
--- /dev/null
+++ b/cells/agent-presentation-continuity/README.md
@@ -0,0 +1,20 @@
+# agent-presentation-continuity
+
+Model-free acceptance coverage for adding, changing, and clearing Agent Spec
+presentation metadata without changing stable identity or the live process
+generation.
+
+The cell begins with the existing positional stable ID and a conflicting
+legacy sibling `name` file. It proves that Agent Spec is authoritative: absent
+presentation does not fall back to the sibling file, and declared `name` and
+`description` appear in the roster after an in-place catalog
+edit. Across add, repeat, change, and clear reconciliations it requires the
+same PTY ID, PID, creation timestamp, and single `session_start` event.
+
+The same transitions must preserve unread and archived messages, context,
+decisions, resources, presence, and terminal transcript. Cleanup uses the
+existing explicit retirement lifecycle and leaves no PTY state.
+
+This cell does not retire the existing `identity` grammar. Schema versioning
+and breaking grammar changes belong to compoundingtech/st2#127; this cell is
+the additive evidence for compoundingtech/st2#128.
diff --git a/cells/agent-presentation-continuity/agent-presentation-continuity.kdl b/cells/agent-presentation-continuity/agent-presentation-continuity.kdl
new file mode 100644
index 00000000..cbbf849c
--- /dev/null
+++ b/cells/agent-presentation-continuity/agent-presentation-continuity.kdl
@@ -0,0 +1,27 @@
+// Additive Agent Spec presentation changes preserve stable identity, runtime generation, and durable state.
+eval {
+  copy "./fixture"
+  max-timeout "90s"
+
+  run "continuity" {
+    command "bash ./continuity.sh"
+  }
+
+  judges {
+    judge "AUTHORITY - Agent Spec presentation ignores the retired sibling name file" {
+      exec "grep -Fqx PRESENTATION-AUTHORITY-GREEN-a128 $RUNS_DIR/continuity.out"
+    }
+    judge "ROSTER - add, change, repeat, and clear project exact presentation fields" {
+      exec "grep -Fqx PRESENTATION-ROSTER-GREEN-a128 $RUNS_DIR/continuity.out"
+    }
+    judge "GENERATION - every presentation-only reconcile preserves PTY id, pid, createdAt, and one session start" {
+      exec "grep -Fqx PRESENTATION-GENERATION-GREEN-a128 $RUNS_DIR/continuity.out"
+    }
+    judge "DURABILITY - inbox, archive, context, decisions, resources, presence, and transcript survive" {
+      exec "grep -Fqx PRESENTATION-DURABILITY-GREEN-a128 $RUNS_DIR/continuity.out"
+    }
+    judge "CLEANUP - explicit retirement leaves no retained PTY state" {
+      exec "grep -Fqx PRESENTATION-CLEANUP-GREEN-a128 $RUNS_DIR/continuity.out"
+    }
+  }
+}
diff --git a/cells/agent-presentation-continuity/fixture/continuity.sh b/cells/agent-presentation-continuity/fixture/continuity.sh
new file mode 100755
index 00000000..31c482ef
--- /dev/null
+++ b/cells/agent-presentation-continuity/fixture/continuity.sh
@@ -0,0 +1,160 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+root="${CATALOG:?CATALOG must be set}"
+net="$root/net"
+spec="$net/agents/pc/worker/agent.kdl"
+original="$root/worker.original.kdl"
+pty_id="pc.worker"
+export PTY_ROOT="$net/pty"
+export XDG_STATE_HOME="$root/state"
+
+cp "$spec" "$original"
+
+pty_at() {
+  env -u PTY_SESSION PTY_ROOT="$PTY_ROOT" pty "$@"
+}
+
+session() {
+  pty_at list --json | jq -cer --arg id "$pty_id" '.[] | select(.name == $id)'
+}
+
+generation() {
+  session | jq -c '{name,pid,createdAt}'
+}
+
+start_count() {
+  jq -s '[.[] | select(.type == "session_start")] | length' "$PTY_ROOT/$pty_id.events.jsonl"
+}
+
+wait_running() {
+  for _ in $(seq 1 100); do
+    test "$(session | jq -r '.status')" = running && return 0
+    sleep 0.05
+  done
+  echo "presentation fixture did not become ready" >&2
+  return 1
+}
+
+retire() {
+  grep -Fq 'retired #true' "$spec" || sed -i '/role "worker"/a\\  retired #true' "$spec"
+}
+
+cleanup() {
+  if test -f "$spec"; then
+    retire 2>/dev/null || true
+    st2 up --once --catalog "$net" --host pc >/dev/null 2>&1 || true
+  fi
+  pty_at kill "$pty_id" >/dev/null 2>&1 || true
+  pty_at rm "$pty_id" >/dev/null 2>&1 || true
+  cp "$original" "$spec" 2>/dev/null || true
+}
+trap cleanup EXIT
+
+st2 validate --catalog "$net" --host pc --strict >/dev/null
+st2 agents --catalog "$net" --host pc --json >"$root/roster-absent.json"
+jq -e '
+  length == 2 and
+  (.[] | select(.identity == "pc.worker") | .name == null and .description == null)
+' "$root/roster-absent.json" >/dev/null
+echo "PRESENTATION-AUTHORITY-GREEN-a128"
+
+st2 up --once --catalog "$net" --host pc >"$root/launch.out"
+grep -Fq 'launched (1): pc.worker' "$root/launch.out"
+wait_running
+before="$(generation)"
+test "$(start_count)" -eq 1
+
+st2 status "$pty_id" --set busy --catalog "$net" --host pc --as "$pty_id" >/dev/null
+printf '%s\n' CONTEXT-NOW-a128 | st2 context write "$pty_id" --catalog "$net" --as "$pty_id"
+st2 context append "$pty_id" --catalog "$net" --as "$pty_id" \
+  --decision DECISION-a128 --why DECISION-WHY-a128
+st2 resource add https://example.invalid/presentation-a128 \
+  --catalog "$net" --as "$pty_id" --title PRESENTATION-RESOURCE-a128 \
+  --tag presentation,continuity --relation output >"$root/resource-ref"
+
+st2 message send "$pty_id" --catalog "$net" --host pc --as pc.sender \
+  --subject ARCHIVED-a128 >/dev/null <<'MSG'
+ARCHIVED-BODY-a128
+MSG
+archived_path=("$net/agents/pc/worker/resources/inbox/"*.md)
+test "${#archived_path[@]}" -eq 1
+archived_name="$(basename "${archived_path[0]}")"
+st2 message archive "$pty_id" "$archived_name" --catalog "$net" --host pc \
+  --as "$pty_id" >/dev/null
+st2 message send "$pty_id" --catalog "$net" --host pc --as pc.sender \
+  --subject UNREAD-a128 >/dev/null <<'MSG'
+UNREAD-BODY-a128
+MSG
+
+for _ in $(seq 1 100); do
+  pty_at peek --plain "$pty_id" 2>/dev/null | grep -Fq PRESENTATION-TRANSCRIPT-a128 && break
+  sleep 0.05
+done
+pty_at peek --plain "$pty_id" | grep -Fq PRESENTATION-TRANSCRIPT-a128
+
+add_fields() {
+  sed -i '/role "worker"/a\\  description "Owns durable identity acceptance"\n  name "Evidence Worker"' "$spec"
+}
+
+assert_generation() {
+  test "$(generation)" = "$before"
+  test "$(start_count)" -eq 1
+}
+
+add_fields
+st2 validate --catalog "$net" --host pc --strict >/dev/null
+st2 up --once --catalog "$net" --host pc >"$root/add.out"
+grep -Fq 'adopted (1): worker' "$root/add.out"
+test -z "$(sed -n '/launched (/p;/torn down (/p' "$root/add.out")"
+assert_generation
+st2 agents --catalog "$net" --host pc --json >"$root/roster-added.json"
+jq -e '
+  .[] | select(.identity == "pc.worker") |
+  .name == "Evidence Worker" and
+  .description == "Owns durable identity acceptance"
+' "$root/roster-added.json" >/dev/null
+
+st2 up --once --catalog "$net" --host pc >"$root/repeat.out"
+grep -Fq 'adopted (1): worker' "$root/repeat.out"
+assert_generation
+
+sed -i 's/name "Evidence Worker"/name "Shared Presentation"/' "$spec"
+sed -i 's/description "Owns durable identity acceptance"/description "Owns changed identity acceptance"/' "$spec"
+st2 up --once --catalog "$net" --host pc >"$root/change.out"
+assert_generation
+st2 agents --catalog "$net" --host pc --json >"$root/roster-changed.json"
+jq -e '
+  .[] | select(.identity == "pc.worker") |
+  .name == "Shared Presentation" and
+  .description == "Owns changed identity acceptance"
+' "$root/roster-changed.json" >/dev/null
+
+sed -i '/^  name "/d;/^  description "/d' "$spec"
+st2 up --once --catalog "$net" --host pc >"$root/clear.out"
+assert_generation
+st2 agents --catalog "$net" --host pc --json >"$root/roster-cleared.json"
+jq -e '
+  .[] | select(.identity == "pc.worker") |
+  .name == null and .description == null
+' "$root/roster-cleared.json" >/dev/null
+echo "PRESENTATION-ROSTER-GREEN-a128"
+echo "PRESENTATION-GENERATION-GREEN-a128"
+
+test "$(st2 status "$pty_id" --catalog "$net" --host pc --as "$pty_id")" = busy
+st2 context read "$pty_id" --catalog "$net" --as "$pty_id" | grep -Fq CONTEXT-NOW-a128
+st2 context read "$pty_id" --catalog "$net" --as "$pty_id" --decisions | grep -Fq DECISION-WHY-a128
+st2 resource ls --catalog "$net" --as "$pty_id" | grep -Fq https://example.invalid/presentation-a128
+test -f "$net/agents/pc/worker/resources/archive/$archived_name"
+grep -Fq ARCHIVED-BODY-a128 "$net/agents/pc/worker/resources/archive/$archived_name"
+grep -Fq UNREAD-BODY-a128 "$net/agents/pc/worker/resources/inbox/"*.md
+pty_at peek --plain "$pty_id" | grep -Fq PRESENTATION-TRANSCRIPT-a128
+echo "PRESENTATION-DURABILITY-GREEN-a128"
+
+retire
+st2 up --once --catalog "$net" --host pc >/dev/null
+pty_at rm "$pty_id" >/dev/null 2>&1 || true
+cp "$original" "$spec"
+trap - EXIT
+test "$(pty_at list --json | jq 'length')" -eq 0
+echo "PRESENTATION-CLEANUP-GREEN-a128"
diff --git a/cells/agent-presentation-continuity/fixture/net/agents/pc/sender/agent.kdl b/cells/agent-presentation-continuity/fixture/net/agents/pc/sender/agent.kdl
new file mode 100644
index 00000000..781b531a
--- /dev/null
+++ b/cells/agent-presentation-continuity/fixture/net/agents/pc/sender/agent.kdl
@@ -0,0 +1,8 @@
+agent "sender" {
+  identity "sender"
+  host "pc"
+  role "fixture"
+  retired #true
+  workspace "$CATALOG/workspace"
+  command "true"
+}
diff --git a/cells/agent-presentation-continuity/fixture/net/agents/pc/worker/agent.kdl b/cells/agent-presentation-continuity/fixture/net/agents/pc/worker/agent.kdl
new file mode 100644
index 00000000..f6be1249
--- /dev/null
+++ b/cells/agent-presentation-continuity/fixture/net/agents/pc/worker/agent.kdl
@@ -0,0 +1,10 @@
+agent "worker" {
+  identity "worker"
+  host "pc"
+  role "worker"
+  workspace "$CATALOG/workspace"
+  env {
+    ST_AGENT "pc.worker"
+  }
+  command "exec bash \"$CATALOG/../task.sh\""
+}
diff --git a/cells/agent-presentation-continuity/fixture/net/agents/pc/worker/name b/cells/agent-presentation-continuity/fixture/net/agents/pc/worker/name
new file mode 100644
index 00000000..710e111d
--- /dev/null
+++ b/cells/agent-presentation-continuity/fixture/net/agents/pc/worker/name
@@ -0,0 +1 @@
+RETIRED-SIBLING-NAME-MUST-NOT-SURFACE
diff --git a/cells/agent-presentation-continuity/fixture/net/workspace/.keep b/cells/agent-presentation-continuity/fixture/net/workspace/.keep
new file mode 100644
index 00000000..ee8c1ee4
--- /dev/null
+++ b/cells/agent-presentation-continuity/fixture/net/workspace/.keep
@@ -0,0 +1 @@
+fixture
diff --git a/cells/agent-presentation-continuity/fixture/task.sh b/cells/agent-presentation-continuity/fixture/task.sh
new file mode 100755
index 00000000..b08aab86
--- /dev/null
+++ b/cells/agent-presentation-continuity/fixture/task.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+printf 'PRESENTATION-TRANSCRIPT-a128\n'
+exec sleep 300
diff --git a/cells/agent-presentation-contract/README.md b/cells/agent-presentation-contract/README.md
new file mode 100644
index 00000000..b7ddcc5b
--- /dev/null
+++ b/cells/agent-presentation-contract/README.md
@@ -0,0 +1,29 @@
+# agent-presentation-contract
+
+Model-free acceptance coverage for stable Agent Spec identity and mutable
+presentation metadata across the native st2 and PTY boundary.
+
+Two live agents deliberately share one display name. Stable IDs remain the
+only st2 routing, authorization, task, and lifecycle keys, while PTY human
+lookup follows its exact-ID-first and fail-closed ambiguity contract. Changing
+or clearing `name` and `description` updates the roster and managed
+PTY metadata without changing the PTY ID, PID, creation timestamp, or process
+generation. Repeating an unchanged reconciliation emits no metadata event.
+Name and description accept at most 160 and 1,000 Unicode scalars respectively;
+empty, untrimmed, multiline, and control text is refused.
+
+Every managed PTY receives the same owned presentation schema, actor path,
+and description tags. Only the primary agent PTY receives Agent Spec
+`name` as its native display name; a secondary task keeps its task-specific
+display behavior across presentation changes.
+
+The same black-box fixture exercises source-preserving presentation authoring:
+operator, self, and supervisor edits succeed; peer edits, Nix-owned sources,
+and JSON/TOML declarations fail with classified receipts. Concurrent edits to
+different presentation fields serialize through the catalog lock and preserve
+both accepted values.
+
+An explicit exact-ID primary-process kill is the lifecycle control: normal
+reconciliation must report the primary as restarted and create a new generation
+without disturbing its secondary task or sibling agent. Explicit retirement
+remains the cleanup boundary.
diff --git a/cells/agent-presentation-contract/agent-presentation-contract.kdl b/cells/agent-presentation-contract/agent-presentation-contract.kdl
new file mode 100644
index 00000000..a463752f
--- /dev/null
+++ b/cells/agent-presentation-contract/agent-presentation-contract.kdl
@@ -0,0 +1,36 @@
+// Stable-ID routing plus non-unique, mutable presentation projected into live PTY metadata.
+eval {
+  copy "./fixture"
+  max-timeout "90s"
+
+  run "contract" {
+    command "bash ./contract.sh"
+  }
+
+  judges {
+    judge "AUTHORING - presentation edits preserve identity and enforce self, supervisor, ownership, and format boundaries" {
+      exec "grep -Fqx PRESENTATION-AUTHORING-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+    judge "SCHEMA - presentation fields enforce Unicode-scalar bounds and roster output is deterministic" {
+      exec "grep -Fqx PRESENTATION-SCHEMA-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+    judge "DUPLICATES - duplicate names are valid while ambiguous PTY references fail closed with stable IDs" {
+      exec "grep -Fqx PRESENTATION-DUPLICATES-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+    judge "ROUTING - st2 message and presence targets resolve stable IDs only" {
+      exec "grep -Fqx PRESENTATION-ROUTING-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+    judge "PROJECTION - name and description changes and removal fully update PTY metadata" {
+      exec "grep -Fqx PRESENTATION-PROJECTION-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+    judge "IDEMPOTENCE - unchanged presentation emits no event and preserves the runtime generation" {
+      exec "grep -Fqx PRESENTATION-IDEMPOTENCE-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+    judge "LIFECYCLE CONTROL - an exact dead primary process is restarted without disturbing sibling tasks" {
+      exec "grep -Fqx PRESENTATION-LIFECYCLE-CONTROL-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+    judge "CLEANUP - explicit retirement leaves no live or retained PTY state" {
+      exec "grep -Fqx PRESENTATION-CLEANUP-GREEN-b128 $RUNS_DIR/contract.out"
+    }
+  }
+}
diff --git a/cells/agent-presentation-contract/fixture/contract.sh b/cells/agent-presentation-contract/fixture/contract.sh
new file mode 100755
index 00000000..c9c6a45f
--- /dev/null
+++ b/cells/agent-presentation-contract/fixture/contract.sh
@@ -0,0 +1,503 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+root="${CATALOG:?CATALOG must be set}"
+net="$root/net"
+alpha_spec="$net/agents/ap/alpha/agent.kdl"
+beta_spec="$net/agents/ap/beta/agent.kdl"
+alpha_original="$root/alpha.original.kdl"
+beta_original="$root/beta.original.kdl"
+export PTY_ROOT="$net/pty"
+export XDG_STATE_HOME="$root/state"
+
+cp "$alpha_spec" "$alpha_original"
+cp "$beta_spec" "$beta_original"
+
+pty_at() {
+  env -u PTY_SESSION PTY_ROOT="$PTY_ROOT" pty "$@"
+}
+
+session() {
+  id="$1"
+  pty_at list --json | jq -cer --arg id "$id" '.[] | select(.name == $id)'
+}
+
+generation() {
+  session "$1" | jq -c '{name,pid,createdAt}'
+}
+
+presentation() {
+  session "$1" | jq -c '{displayName,tags}'
+}
+
+event_count() {
+  id="$1"
+  type="$2"
+  jq -s --arg type "$type" '[.[] | select(.type == $type)] | length' "$PTY_ROOT/$id.events.jsonl"
+}
+
+last_metadata_event() {
+  local id="$1"
+  jq -cs '[.[] | select(.type == "metadata_change")] | last' "$PTY_ROOT/$id.events.jsonl"
+}
+
+wait_running() {
+  id="$1"
+  for _ in $(seq 1 100); do
+    test "$(session "$id" | jq -r '.status')" = running && return 0
+    sleep 0.05
+  done
+  printf '%s did not become ready\n' "$id" >&2
+  return 1
+}
+
+retire() {
+  spec="$1"
+  grep -Fq 'retired #true' "$spec" || sed -i '/role "worker"/a\\  retired #true' "$spec"
+}
+
+cleanup() {
+  for spec in "$alpha_spec" "$beta_spec"; do
+    test ! -f "$spec" || retire "$spec" 2>/dev/null || true
+  done
+  st2 up --once --catalog "$net" --host ap >/dev/null 2>&1 || true
+  for id in ap.alpha ap.alpha.helper ap.beta; do
+    pty_at kill "$id" >/dev/null 2>&1 || true
+    pty_at rm "$id" >/dev/null 2>&1 || true
+  done
+  cp "$alpha_original" "$alpha_spec" 2>/dev/null || true
+  cp "$beta_original" "$beta_spec" 2>/dev/null || true
+}
+trap cleanup EXIT
+
+invalid="$root/invalid"
+mkdir -p "$invalid/agents/ap/empty" "$invalid/workspace"
+cat >"$invalid/agents/ap/empty/agent.kdl" <<'KDL'
+agent "empty" {
+  identity "empty"
+  host "ap"
+  name ""
+  description ""
+  workspace "$CATALOG/workspace"
+  command "true"
+}
+KDL
+set +e
+st2 validate --catalog "$invalid" --host ap --strict >"$root/invalid.out" 2>&1
+invalid_rc=$?
+set -e
+test "$invalid_rc" -ne 0
+
+authoring="$root/authoring"
+mkdir -p \
+  "$authoring/agents/ap/root" \
+  "$authoring/agents/ap/child" \
+  "$authoring/agents/ap/grandchild" \
+  "$authoring/agents/ap/sibling" \
+  "$authoring/agents/ap/nix" \
+  "$authoring/agents/ap/json" \
+  "$authoring/agents/ap/toml"
+cat >"$authoring/agents/ap/root/agent.kdl" <<'KDL'
+// preserve-root-comment-b128
+agent "root" {
+  identity "root"
+  host "ap"
+  role "fixture"
+  meta { managed-by "catalog"; keep "unchanged" }
+  command "true"
+}
+KDL
+cat >"$authoring/agents/ap/child/agent.kdl" <<'KDL'
+agent "child" {
+  identity "child"
+  host "ap"
+  role "fixture"
+  supervisor "ap.root"
+  meta { managed-by "catalog" }
+  command "true"
+}
+KDL
+cat >"$authoring/agents/ap/grandchild/agent.kdl" <<'KDL'
+agent "grandchild" {
+  identity "grandchild"
+  host "ap"
+  role "fixture"
+  supervisor "ap.child"
+  meta { managed-by "catalog" }
+  command "true"
+}
+KDL
+cat >"$authoring/agents/ap/sibling/agent.kdl" <<'KDL'
+agent "sibling" {
+  identity "sibling"
+  host "ap"
+  role "fixture"
+  supervisor "ap.root"
+  meta { managed-by "catalog" }
+  command "true"
+}
+KDL
+cat >"$authoring/agents/ap/nix/agent.kdl" <<'KDL'
+agent "nix" {
+  identity "nix"
+  host "ap"
+  role "fixture"
+  supervisor "ap.root"
+  meta { managed-by "nix" }
+  command "true"
+}
+KDL
+cat >"$authoring/agents/ap/json/agent.json" <<'JSON'
+{"identity":"json","host":"ap","role":"fixture","command":"true"}
+JSON
+cat >"$authoring/agents/ap/toml/agent.toml" <<'TOML'
+identity = "toml"
+host = "ap"
+role = "fixture"
+command = "true"
+TOML
+
+env -u ST_AGENT st2 --catalog "$authoring" rename ap.root "Root Operator" --host ap --json \
+  | jq -e '. == {result:"changed",identity:"ap.root",field:"name",value:"Root Operator",retired:false}' \
+  >/dev/null
+
+name_limit="$(jq -nr '"é" * 160')"
+description_limit="$(jq -nr '"é" * 1000')"
+for boundary in \
+  "rename|$name_limit" \
+  "describe|$description_limit"
+do
+  IFS='|' read -r command value <<<"$boundary"
+  env -u ST_AGENT st2 --catalog "$authoring" "$command" ap.root "$value" --host ap --json \
+    | jq -e --arg value "$value" '.result == "changed" and .value == $value' >/dev/null
+done
+st2 validate --catalog "$authoring" --host ap --strict >/dev/null
+
+expect_invalid_presentation() {
+  local command="$1"
+  local value="$2"
+  set +e
+  env -u ST_AGENT st2 --catalog "$authoring" "$command" ap.root "$value" --host ap --json \
+    >"$root/invalid-presentation.json" 2>"$root/invalid-presentation.err"
+  invalid_presentation_rc=$?
+  set -e
+  test "$invalid_presentation_rc" -ne 0
+  jq -e '.result == "error" and .code == "invalid-presentation"' \
+    "$root/invalid-presentation.json" >/dev/null
+}
+expect_invalid_presentation rename "$(jq -nr '"é" * 161')"
+expect_invalid_presentation describe "$(jq -nr '"é" * 1001')"
+expect_invalid_presentation rename ""
+expect_invalid_presentation rename " leading"
+expect_invalid_presentation rename "trailing "
+expect_invalid_presentation rename $'two\nlines'
+expect_invalid_presentation rename $'control\x01character'
+expect_invalid_presentation describe ""
+expect_invalid_presentation describe " leading"
+expect_invalid_presentation describe "trailing "
+expect_invalid_presentation describe $'two\nlines'
+expect_invalid_presentation describe $'control\x01character'
+env -u ST_AGENT st2 --catalog "$authoring" rename ap.root "Root Operator" --host ap --json >/dev/null
+env -u ST_AGENT st2 --catalog "$authoring" describe ap.root --clear --host ap --json >/dev/null
+
+ST_AGENT=ap.root st2 --catalog "$authoring" describe ap.child "Owned by root" --host ap --json \
+  | jq -e '.result == "changed" and .identity == "ap.child" and .field == "description"' >/dev/null
+ST_AGENT=ap.root st2 --catalog "$authoring" describe ap.grandchild "Owned by ancestor" --host ap --json \
+  | jq -e '.result == "changed" and .identity == "ap.grandchild" and .field == "description" and .value == "Owned by ancestor"' >/dev/null
+grep -Fq 'description "Owned by ancestor"' "$authoring/agents/ap/grandchild/agent.kdl"
+ST_AGENT=ap.child st2 --catalog "$authoring" rename ap.child "Child Self" --host ap --json \
+  | jq -e '.result == "changed" and .identity == "ap.child" and .field == "name"' >/dev/null
+ST_AGENT=ap.child st2 --catalog "$authoring" rename ap.child "Child Self" --host ap --json \
+  | jq -e '.result == "unchanged" and .value == "Child Self"' >/dev/null
+
+ST_AGENT=ap.root st2 --catalog "$authoring" rename ap.child "Concurrent Child" --host ap --json \
+  >"$root/concurrent-name.json" &
+concurrent_name_pid=$!
+ST_AGENT=ap.root st2 --catalog "$authoring" describe ap.child "Concurrent description" --host ap --json \
+  >"$root/concurrent-description.json" &
+concurrent_description_pid=$!
+wait "$concurrent_name_pid"
+wait "$concurrent_description_pid"
+jq -e '.result == "changed" and .field == "name" and .value == "Concurrent Child"' \
+  "$root/concurrent-name.json" >/dev/null
+jq -e '.result == "changed" and .field == "description" and .value == "Concurrent description"' \
+  "$root/concurrent-description.json" >/dev/null
+grep -Fq 'name "Concurrent Child"' "$authoring/agents/ap/child/agent.kdl"
+grep -Fq 'description "Concurrent description"' "$authoring/agents/ap/child/agent.kdl"
+grep -Fq 'supervisor "ap.root"' "$authoring/agents/ap/child/agent.kdl"
+grep -Fq 'meta { managed-by "catalog" }' "$authoring/agents/ap/child/agent.kdl"
+grep -Fq 'command "true"' "$authoring/agents/ap/child/agent.kdl"
+
+for refusal in \
+  'ap.child|rename|ap.sibling|peer denied|presentation-not-authorized' \
+  'ap.root|describe|ap.nix|nix denied|nix-managed-declaration' \
+  'operator|describe|ap.json|json denied|unsupported-declaration-format' \
+  'operator|describe|ap.toml|toml denied|unsupported-declaration-format'
+do
+  IFS='|' read -r actor command target value code <<<"$refusal"
+  if test "$actor" = operator; then
+    actor_env=(env -u ST_AGENT)
+  else
+    actor_env=(env "ST_AGENT=$actor")
+  fi
+  set +e
+  "${actor_env[@]}" st2 --catalog "$authoring" "$command" "$target" "$value" --host ap --json \
+    >"$root/$target-$command-refusal.json" 2>"$root/$target-$command-refusal.err"
+  refusal_rc=$?
+  set -e
+  test "$refusal_rc" -ne 0
+  jq -e --arg code "$code" '.result == "error" and .code == $code' \
+    "$root/$target-$command-refusal.json" >/dev/null
+done
+
+ST_AGENT=ap.root st2 --catalog "$authoring" describe ap.child --clear --host ap --json \
+  | jq -e '.result == "changed" and .value == null' >/dev/null
+env -u ST_AGENT st2 --catalog "$authoring" rename ap.root --clear --host ap --json \
+  | jq -e '. == {result:"changed",identity:"ap.root",field:"name",value:null,retired:false}' >/dev/null
+! grep -Fq 'name "' "$authoring/agents/ap/root/agent.kdl"
+grep -Fqx '// preserve-root-comment-b128' "$authoring/agents/ap/root/agent.kdl"
+grep -Fq 'keep "unchanged"' "$authoring/agents/ap/root/agent.kdl"
+grep -Fq 'identity "root"' "$authoring/agents/ap/root/agent.kdl"
+echo "PRESENTATION-AUTHORING-GREEN-b128"
+
+st2 validate --catalog "$net" --host ap --strict >/dev/null
+st2 agents --catalog "$net" --host ap --json >"$root/roster.json"
+st2 agents --catalog "$net" --host ap --json >"$root/roster-repeat.json"
+cmp "$root/roster.json" "$root/roster-repeat.json"
+jq -e '
+  [ .[] | select(.identity == "ap.alpha" or .identity == "ap.beta") ] == [
+    {
+      "identity": "ap.alpha",
+      "status": "offline",
+      "name": "Shared Worker",
+      "description": "Owns alpha acceptance",
+      "retired": false,
+      "resources": []
+    },
+    {
+      "identity": "ap.beta",
+      "status": "offline",
+      "name": "Shared Worker",
+      "description": "Owns beta acceptance",
+      "retired": false,
+      "resources": []
+    }
+  ]
+' "$root/roster.json" >/dev/null
+echo "PRESENTATION-SCHEMA-GREEN-b128"
+
+st2 up --once --catalog "$net" --host ap >"$root/launch.out"
+wait_running ap.alpha
+wait_running ap.alpha.helper
+wait_running ap.beta
+alpha_before="$(generation ap.alpha)"
+alpha_helper_before="$(generation ap.alpha.helper)"
+alpha_helper_display="$(session ap.alpha.helper | jq -c '.displayName // null')"
+beta_before="$(generation ap.beta)"
+test "$(event_count ap.alpha session_start)" -eq 1
+test "$(event_count ap.alpha.helper session_start)" -eq 1
+test "$(event_count ap.beta session_start)" -eq 1
+test "$(session ap.alpha | jq -r '.displayName')" = "Shared Worker"
+test "$(session ap.beta | jq -r '.displayName')" = "Shared Worker"
+test "$(session ap.alpha.helper | jq -r '.displayName // "absent"')" != "Shared Worker"
+jq -e '
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.alpha" and
+  .tags["agent.presentation.description"] == "Owns alpha acceptance" and
+  (.tags | has("agent.presentation.name") | not)
+' <<<"$(session ap.alpha)" >/dev/null
+jq -e '
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.beta" and
+  .tags["agent.presentation.description"] == "Owns beta acceptance" and
+  (.tags | has("agent.presentation.name") | not)
+' <<<"$(session ap.beta)" >/dev/null
+jq -e '
+  .tags["purpose"] == "secondary" and
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.alpha" and
+  .tags["agent.presentation.description"] == "Owns alpha acceptance" and
+  (.tags | has("agent.presentation.name") | not)
+' <<<"$(session ap.alpha.helper)" >/dev/null
+
+set +e
+pty_at peek --plain "Shared Worker" >"$root/ambiguous.out" 2>"$root/ambiguous.err"
+ambiguous_rc=$?
+set -e
+test "$ambiguous_rc" -ne 0
+grep -Fq ap.alpha "$root/ambiguous.err"
+grep -Fq ap.beta "$root/ambiguous.err"
+test "$(grep -o 'ap\.alpha\|ap\.beta' "$root/ambiguous.err" | paste -sd, -)" = ap.alpha,ap.beta
+pty_at peek --plain ap.alpha | grep -Fq alpha-GENERATION-1-b128
+echo "PRESENTATION-DUPLICATES-GREEN-b128"
+
+st2 message send ap.alpha --catalog "$net" --host ap --as ap.sender \
+  --subject STABLE-ID-ROUTING-b128 >/dev/null <<'MSG'
+STABLE-ID-BODY-b128
+MSG
+grep -Fq STABLE-ID-BODY-b128 "$net/agents/ap/alpha/resources/inbox/"*.md
+set +e
+st2 message send "Shared Worker" --catalog "$net" --host ap --as ap.sender \
+  --subject DISPLAY-MUST-NOT-ROUTE-b128 \
+  >"$root/display-route.out" 2>"$root/display-route.err" <<'MSG'
+DISPLAY-MUST-NOT-ROUTE-b128
+MSG
+display_route_rc=$?
+st2 status "Shared Worker" --set busy --catalog "$net" --host ap --as ap.sender \
+  >"$root/display-status.out" 2>"$root/display-status.err"
+display_status_rc=$?
+st2 message send "Owns alpha acceptance" --catalog "$net" --host ap --as ap.sender \
+  --subject DESCRIPTION-MUST-NOT-ROUTE-b128 \
+  >"$root/description-route.out" 2>"$root/description-route.err" <<'MSG'
+DESCRIPTION-MUST-NOT-ROUTE-b128
+MSG
+description_route_rc=$?
+set -e
+test "$display_route_rc" -ne 0
+test "$display_status_rc" -ne 0
+test "$description_route_rc" -ne 0
+! grep -RFq DISPLAY-MUST-NOT-ROUTE-b128 "$net/agents/ap"
+! grep -RFq DESCRIPTION-MUST-NOT-ROUTE-b128 "$net"
+echo "PRESENTATION-ROUTING-GREEN-b128"
+
+pty_at tag ap.alpha external.keep=untouched >/dev/null
+alpha_metadata_events="$(event_count ap.alpha metadata_change)"
+alpha_display_events="$(event_count ap.alpha display_name_change)"
+alpha_tag_events="$(event_count ap.alpha tags_change)"
+sed -i 's/name "Shared Worker"/name "ap.beta"/' "$alpha_spec"
+st2 up --once --catalog "$net" --host ap >"$root/id-collision.out"
+test "$(generation ap.alpha)" = "$alpha_before"
+test "$(generation ap.alpha.helper)" = "$alpha_helper_before"
+test "$(generation ap.beta)" = "$beta_before"
+test "$(session ap.alpha | jq -r '.displayName')" = ap.beta
+test "$(session ap.alpha.helper | jq -c '.displayName // null')" = "$alpha_helper_display"
+jq -e '
+  .tags["external.keep"] == "untouched" and
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.alpha" and
+  .tags["agent.presentation.description"] == "Owns alpha acceptance"
+' <<<"$(session ap.alpha)" >/dev/null
+test "$(event_count ap.alpha metadata_change)" -eq $((alpha_metadata_events + 1))
+test "$(event_count ap.alpha display_name_change)" -eq "$alpha_display_events"
+test "$(event_count ap.alpha tags_change)" -eq "$alpha_tag_events"
+jq -e '
+  .previous == {displayName:"Shared Worker"} and
+  .value == {displayName:"ap.beta"}
+' <<<"$(last_metadata_event ap.alpha)" >/dev/null
+pty_at peek --plain ap.beta | grep -Fq beta-GENERATION-1-b128
+
+sed -i 's/name "ap.beta"/name "Alpha Renamed"/' "$alpha_spec"
+sed -i 's/description "Owns alpha acceptance"/description "Owns renamed alpha acceptance"/' "$alpha_spec"
+old_projection="$(presentation ap.alpha)"
+rm -f "$root/change.done"
+(
+  while ! test -f "$root/change.done"; do
+    presentation ap.alpha >>"$root/change-observations.jsonl"
+  done
+) &
+observer_pid=$!
+st2 up --once --catalog "$net" --host ap >"$root/change.out"
+touch "$root/change.done"
+wait "$observer_pid"
+test "$(generation ap.alpha)" = "$alpha_before"
+test "$(generation ap.alpha.helper)" = "$alpha_helper_before"
+test "$(generation ap.beta)" = "$beta_before"
+test "$(event_count ap.alpha session_start)" -eq 1
+test "$(session ap.alpha | jq -r '.displayName')" = "Alpha Renamed"
+new_projection="$(presentation ap.alpha)"
+jq -s -e --argjson old "$old_projection" --argjson new "$new_projection" \
+  'length > 0 and all(. == $old or . == $new)' "$root/change-observations.jsonl" >/dev/null
+jq -e '
+  .tags["external.keep"] == "untouched" and
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.alpha" and
+  .tags["agent.presentation.description"] == "Owns renamed alpha acceptance" and
+  (.tags | has("agent.presentation.name") | not)
+' <<<"$(session ap.alpha)" >/dev/null
+jq -e '
+  .tags["purpose"] == "secondary" and
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.alpha" and
+  .tags["agent.presentation.description"] == "Owns renamed alpha acceptance"
+' <<<"$(session ap.alpha.helper)" >/dev/null
+test "$(session ap.alpha.helper | jq -c '.displayName // null')" = "$alpha_helper_display"
+test "$(event_count ap.alpha metadata_change)" -eq $((alpha_metadata_events + 2))
+test "$(event_count ap.alpha display_name_change)" -eq "$alpha_display_events"
+test "$(event_count ap.alpha tags_change)" -eq "$alpha_tag_events"
+jq -e '
+  .previous == {
+    displayName:"ap.beta",
+    tags:{"agent.presentation.description":"Owns alpha acceptance"}
+  } and
+  .value == {
+    displayName:"Alpha Renamed",
+    tags:{"agent.presentation.description":"Owns renamed alpha acceptance"}
+  }
+' <<<"$(last_metadata_event ap.alpha)" >/dev/null
+
+changed_events="$(wc -l <"$PTY_ROOT/ap.alpha.events.jsonl")"
+st2 up --once --catalog "$net" --host ap >"$root/idempotent.out"
+test "$(generation ap.alpha)" = "$alpha_before"
+test "$(wc -l <"$PTY_ROOT/ap.alpha.events.jsonl")" -eq "$changed_events"
+echo "PRESENTATION-IDEMPOTENCE-GREEN-b128"
+
+sed -i '/^  name "/d;/^  description "/d' "$alpha_spec"
+st2 up --once --catalog "$net" --host ap >"$root/clear.out"
+test "$(generation ap.alpha)" = "$alpha_before"
+test "$(generation ap.alpha.helper)" = "$alpha_helper_before"
+test "$(session ap.alpha | jq -r '.displayName // "absent"')" = absent
+test "$(event_count ap.alpha metadata_change)" -eq $((alpha_metadata_events + 3))
+test "$(event_count ap.alpha display_name_change)" -eq "$alpha_display_events"
+test "$(event_count ap.alpha tags_change)" -eq "$alpha_tag_events"
+jq -e '
+  .previous == {
+    displayName:"Alpha Renamed",
+    tags:{"agent.presentation.description":"Owns renamed alpha acceptance"}
+  } and
+  .value == {
+    displayName:null,
+    tags:{"agent.presentation.description":null}
+  }
+' <<<"$(last_metadata_event ap.alpha)" >/dev/null
+jq -e '
+  .tags["external.keep"] == "untouched" and
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.alpha" and
+  (.tags | has("agent.presentation.description") | not) and
+  (.tags | has("agent.presentation.name") | not)
+' <<<"$(session ap.alpha)" >/dev/null
+jq -e '
+  .tags["purpose"] == "secondary" and
+  .tags["agent.presentation.schema"] == "1" and
+  .tags["agent.actor.path"] == "ap.alpha" and
+  (.tags | has("agent.presentation.description") | not)
+' <<<"$(session ap.alpha.helper)" >/dev/null
+test "$(session ap.alpha.helper | jq -c '.displayName // null')" = "$alpha_helper_display"
+st2 agents --catalog "$net" --host ap --json >"$root/cleared-roster.json"
+jq -e '.[] | select(.identity == "ap.alpha") | .name == null and .description == null' \
+  "$root/cleared-roster.json" >/dev/null
+echo "PRESENTATION-PROJECTION-GREEN-b128"
+
+pty_at kill ap.alpha >/dev/null
+test "$(session ap.alpha | jq -r '.status')" != running
+st2 up --once --catalog "$net" --host ap >"$root/lifecycle.out"
+wait_running ap.alpha
+grep -Fq 'restarted (1): ap.alpha' "$root/lifecycle.out"
+test "$(cat "$net/alpha-count")" -eq 2
+test "$(generation ap.alpha)" != "$alpha_before"
+test "$(event_count ap.alpha session_start)" -eq 1
+test "$(generation ap.alpha.helper)" = "$alpha_helper_before"
+test "$(generation ap.beta)" = "$beta_before"
+echo "PRESENTATION-LIFECYCLE-CONTROL-GREEN-b128"
+
+retire "$alpha_spec"
+retire "$beta_spec"
+st2 up --once --catalog "$net" --host ap >/dev/null
+for id in ap.alpha ap.alpha.helper ap.beta; do
+  pty_at rm "$id" >/dev/null 2>&1 || true
+done
+cp "$alpha_original" "$alpha_spec"
+cp "$beta_original" "$beta_spec"
+trap - EXIT
+test "$(pty_at list --json | jq 'length')" -eq 0
+echo "PRESENTATION-CLEANUP-GREEN-b128"
diff --git a/cells/agent-presentation-contract/fixture/net/agents/ap/alpha/agent.kdl b/cells/agent-presentation-contract/fixture/net/agents/ap/alpha/agent.kdl
new file mode 100644
index 00000000..412a092a
--- /dev/null
+++ b/cells/agent-presentation-contract/fixture/net/agents/ap/alpha/agent.kdl
@@ -0,0 +1,20 @@
+agent "alpha" {
+  identity "alpha"
+  host "ap"
+  role "worker"
+  name "Shared Worker"
+  description "Owns alpha acceptance"
+  workspace "$CATALOG/workspace"
+  env {
+    ST_AGENT "ap.alpha"
+  }
+  command "exec bash \"$CATALOG/../task.sh\" alpha"
+  pty "helper" {
+    id "ap.alpha.helper"
+    command "exec sleep 300"
+    tags purpose="secondary"
+    env {
+      ST_AGENT "ap.alpha"
+    }
+  }
+}
diff --git a/cells/agent-presentation-contract/fixture/net/agents/ap/beta/agent.kdl b/cells/agent-presentation-contract/fixture/net/agents/ap/beta/agent.kdl
new file mode 100644
index 00000000..53891cb5
--- /dev/null
+++ b/cells/agent-presentation-contract/fixture/net/agents/ap/beta/agent.kdl
@@ -0,0 +1,12 @@
+agent "beta" {
+  identity "beta"
+  host "ap"
+  role "worker"
+  name "Shared Worker"
+  description "Owns beta acceptance"
+  workspace "$CATALOG/workspace"
+  env {
+    ST_AGENT "ap.beta"
+  }
+  command "exec bash \"$CATALOG/../task.sh\" beta"
+}
diff --git a/cells/agent-presentation-contract/fixture/net/agents/ap/sender/agent.kdl b/cells/agent-presentation-contract/fixture/net/agents/ap/sender/agent.kdl
new file mode 100644
index 00000000..06ef2ddc
--- /dev/null
+++ b/cells/agent-presentation-contract/fixture/net/agents/ap/sender/agent.kdl
@@ -0,0 +1,8 @@
+agent "sender" {
+  identity "sender"
+  host "ap"
+  role "fixture"
+  retired #true
+  workspace "$CATALOG/workspace"
+  command "true"
+}
diff --git a/cells/agent-presentation-contract/fixture/net/workspace/.keep b/cells/agent-presentation-contract/fixture/net/workspace/.keep
new file mode 100644
index 00000000..ee8c1ee4
--- /dev/null
+++ b/cells/agent-presentation-contract/fixture/net/workspace/.keep
@@ -0,0 +1 @@
+fixture
diff --git a/cells/agent-presentation-contract/fixture/task.sh b/cells/agent-presentation-contract/fixture/task.sh
new file mode 100755
index 00000000..5b3724b2
--- /dev/null
+++ b/cells/agent-presentation-contract/fixture/task.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+label="${1:?task label required}"
+count_file="${CATALOG:?CATALOG must be set}/$label-count"
+count=0
+test ! -f "$count_file" || count="$(cat "$count_file")"
+count=$((count + 1))
+printf '%s\n' "$count" >"$count_file"
+printf '%s-GENERATION-%s-b128\n' "$label" "$count"
+exec sleep 300
diff --git a/docs/vrs/spec.md b/docs/vrs/spec.md
index ab2b1f31..546917f9 100644
--- a/docs/vrs/spec.md
+++ b/docs/vrs/spec.md
@@ -81,6 +81,12 @@ and continues or stops.
   A speculative claim cannot become normative merely by editing the spec. A
   proposed behavior change updates both the canonical contract and its
   maintained proof cells before any implementation claims conformance.
+- The model-free `agent-presentation-contract` and
+  `agent-presentation-continuity` cells prove the stable-identity/presentation
+  split, constrained authoring, exact-ID routing, atomic PTY projection,
+  no-restart reconciliation, durable-state continuity, and lifecycle controls.
+  Their accepted evidence is extracted into the stable identity and
+  presentation section of `AGENT-SPEC.md`.
 - Harness differences are recorded when the same contract needs different
   Claude and Codex mechanisms. They do not silently change the contract.
 - **R11:** Adding a scenario does not require a custom runner path. Its
diff --git a/evidence/harness-exclusions.tsv b/evidence/harness-exclusions.tsv
index 2ac5f66a..074e9efc 100644
--- a/evidence/harness-exclusions.tsv
+++ b/evidence/harness-exclusions.tsv
@@ -1,5 +1,7 @@
 cell	surface	reason
 adopt-only-migration	cell	deterministic native adoption/replacement lifecycle probe; no harness seat
+agent-presentation-continuity	cell	deterministic native presentation continuity probe; no harness seat
+agent-presentation-contract	cell	deterministic native Agent Spec and PTY presentation probe; no harness seat
 agent-spec-resource-bindings	cell	deterministic native Agent Spec Resource-envelope probe; no harness seat
 context-resource-continuity	cell	deterministic native context/resource restart probe; no harness seat
 docs	judge:cold-reader	one-shot offline Claude print grader; no bus identity, DING, or hook surface