diff --git a/decnet/profiler/behave_shell/_features/__init__.py b/decnet/profiler/behave_shell/_features/__init__.py
index b4292136..7cd4640e 100644
--- a/decnet/profiler/behave_shell/_features/__init__.py
+++ b/decnet/profiler/behave_shell/_features/__init__.py
@@ -11,6 +11,9 @@ from typing import Callable, Iterable
 from decnet_behave_core.spec.envelope import Observation
 
 from decnet.profiler.behave_shell._ctx import SessionContext
+from decnet.profiler.behave_shell._features.cognitive import (
+    inter_command_latency_class,
+)
 from decnet.profiler.behave_shell._features.motor import (
     input_modality,
     paste_burst_rate,
@@ -21,4 +24,5 @@ FeatureFn = Callable[[SessionContext], Iterable[Observation]]
 FEATURES: tuple[FeatureFn, ...] = (
     input_modality,
     paste_burst_rate,
+    inter_command_latency_class,
 )
diff --git a/decnet/profiler/behave_shell/_features/cognitive.py b/decnet/profiler/behave_shell/_features/cognitive.py
new file mode 100644
index 00000000..cb14d0f7
--- /dev/null
+++ b/decnet/profiler/behave_shell/_features/cognitive.py
@@ -0,0 +1,61 @@
+"""``cognitive.*`` feature functions.
+
+Step 5: ``cognitive.inter_command_latency_class``.
+Step 6: ``cognitive.command_branch_diversity``.
+Step 7: ``cognitive.feedback_loop_engagement``.
+Step 8: ``cognitive.inter_command_consistency``.
+"""
+from __future__ import annotations
+
+import statistics
+from typing import Iterator
+
+from decnet_behave_core.spec.envelope import Observation
+
+from decnet.profiler.behave_shell._ctx import SessionContext
+from decnet.profiler.behave_shell._features._emit import make_observation
+from decnet.profiler.behave_shell._thresholds import (
+    INTER_CMD_DELIBERATE_MAX,
+    INTER_CMD_INSTANT_MAX,
+    INTER_CMD_LLM_HEAVYWEIGHT_MAX,
+    INTER_CMD_LLM_LIGHTWEIGHT_MAX,
+    INTER_CMD_TYPING_MAX,
+    MIN_COMMANDS_FOR_FULL_CONFIDENCE,
+)
+
+
+def _bucket_inter_cmd_latency(median_iat: float) -> str:
+    if median_iat <= INTER_CMD_INSTANT_MAX:
+        return "instant"
+    if median_iat <= INTER_CMD_TYPING_MAX:
+        return "typing_speed"
+    if median_iat <= INTER_CMD_DELIBERATE_MAX:
+        return "deliberate"
+    if median_iat <= INTER_CMD_LLM_LIGHTWEIGHT_MAX:
+        return "llm_lightweight"
+    if median_iat <= INTER_CMD_LLM_HEAVYWEIGHT_MAX:
+        return "llm_heavyweight"
+    return "long"
+
+
+def inter_command_latency_class(ctx: SessionContext) -> Iterator[Observation]:
+    """Emit ``cognitive.inter_command_latency_class``.
+
+    Operator's *thinking pace* between commands, bucketed against
+    calibrated thresholds. Splits LW-sim / CLAUDE-FF / CLAUDE-CL.
+    """
+    if not ctx.inter_cmd_iats:
+        return
+    median_iat = statistics.median(ctx.inter_cmd_iats)
+    bucket = _bucket_inter_cmd_latency(median_iat)
+    # Sample-size honesty: < 5 commands → halve confidence
+    if len(ctx.commands) < MIN_COMMANDS_FOR_FULL_CONFIDENCE:
+        confidence = 0.40
+    else:
+        confidence = 0.80
+    yield make_observation(
+        ctx,
+        primitive="cognitive.inter_command_latency_class",
+        value=bucket,
+        confidence=confidence,
+    )
diff --git a/decnet/profiler/behave_shell/_thresholds.py b/decnet/profiler/behave_shell/_thresholds.py
index 843373c1..09e25c78 100644
--- a/decnet/profiler/behave_shell/_thresholds.py
+++ b/decnet/profiler/behave_shell/_thresholds.py
@@ -35,3 +35,46 @@ MODALITY_TYPED_MAX: float = 0.05
 # habit signal, input_modality is the dominant-channel signal.
 PASTE_RATE_HABITUAL_MIN: float = 0.50
 PASTE_RATE_OCCASIONAL_MIN: float = 0.10
+
+# ── cognitive.inter_command_latency_class (Step 5) ──────────────────────────
+# Bucket edges (seconds) for the median inter-command IAT. Prototype
+# values; v0.2 splits the original llm_roundtrip 2-8s band into
+# llm_lightweight (orchestrated agents w/ small models / terse prompts) and
+# llm_heavyweight (reasoning-class agents in tool loops with text
+# generation between calls). Empirical anchor: Claude Opus driving recon
+# via tmux send-keys produced a median of 15.5s.
+INTER_CMD_INSTANT_MAX: float = 0.30
+INTER_CMD_TYPING_MAX: float = 1.50
+INTER_CMD_DELIBERATE_MAX: float = 2.00
+INTER_CMD_LLM_LIGHTWEIGHT_MAX: float = 8.00
+INTER_CMD_LLM_HEAVYWEIGHT_MAX: float = 30.00
+
+# Sample-size floor for inter-command IAT primitives. Below this we
+# halve the confidence per BEHAVE-EXTRACTOR.md "sample-size honesty".
+MIN_COMMANDS_FOR_FULL_CONFIDENCE: int = 5
+
+# ── cognitive.command_branch_diversity (Step 6) ─────────────────────────────
+# unique_first_tokens / total_commands ratio. Empirical (CLAUDE-FF vs
+# CLAUDE-CL on 2026-05-02): fire-and-forget runs ~10 distinct tools (ratio
+# near 1.0) → linear_playbook; closed-loop runs ~5-6 tools with the same
+# tool re-invoked → adaptive_branching.
+BRANCH_DIVERSITY_LINEAR_MIN: float = 0.80   # >= → linear_playbook
+BRANCH_DIVERSITY_ADAPTIVE_MAX: float = 0.60  # <= → adaptive_branching
+# Between is the ambiguous middle band — bias toward adaptive (the
+# operator is reusing tools).
+
+# ── cognitive.feedback_loop_engagement (Step 7) ─────────────────────────────
+# Pearson r threshold for "the operator's pause grew with the volume of
+# preceding output". |r| > this → significant; sign carries direction.
+FEEDBACK_CORRELATION_MIN: float = 0.30
+# Need at least this many (output_bytes, next_pause) pairs to even
+# attempt a correlation. Below this the answer is "unknown".
+FEEDBACK_MIN_PAIRS: int = 5
+
+# ── cognitive.inter_command_consistency (Step 8) ────────────────────────────
+# CV (stdev / mean) of inter-command IATs. Empirical (this corpus):
+# human session CV=0.94 → variable; LLM-simulated CV=0.24 → metronomic;
+# anything beyond 1.5 is heuristically "bimodal" (real bimodal detection
+# via Hartigan dip is filed for v0.2).
+PAUSE_CV_METRONOMIC_MAX: float = 0.40
+PAUSE_CV_BIMODAL_MIN: float = 1.50
diff --git a/tests/profiler/behave_shell/test_cognitive_inter_command_latency_class.py b/tests/profiler/behave_shell/test_cognitive_inter_command_latency_class.py
new file mode 100644
index 00000000..f412fda5
--- /dev/null
+++ b/tests/profiler/behave_shell/test_cognitive_inter_command_latency_class.py
@@ -0,0 +1,81 @@
+"""Step 5: ``cognitive.inter_command_latency_class``."""
+from __future__ import annotations
+
+from decnet.profiler.behave_shell import extract_session
+from decnet.profiler.behave_shell._parse import AsciinemaEvent
+
+
+def _of(observations: list, primitive: str):
+    obs = [o for o in observations if o.primitive == primitive]
+    assert len(obs) == 1, f"expected exactly one {primitive}, got {len(obs)}"
+    return obs[0]
+
+
+def _command_stream(starts: list[float]) -> list[AsciinemaEvent]:
+    """Build an input stream that yields commands at the given start times."""
+    events: list[AsciinemaEvent] = []
+    for s in starts:
+        events.append((s, "i", "x"))
+        events.append((s + 0.05, "i", "\r"))
+    return events
+
+
+def test_no_commands_means_no_observation() -> None:
+    out = list(extract_session([], sid="lat-empty"))
+    assert [o for o in out if o.primitive == "cognitive.inter_command_latency_class"] == []
+
+
+def test_single_command_no_iat_no_observation() -> None:
+    out = list(extract_session(_command_stream([0.0]), sid="lat-1"))
+    assert [o for o in out if o.primitive == "cognitive.inter_command_latency_class"] == []
+
+
+def test_instant_bucket() -> None:
+    # IATs of 0.1s — well under 0.30 cap
+    starts = [i * 0.15 for i in range(6)]
+    out = list(extract_session(_command_stream(starts), sid="lat-instant"))
+    assert _of(out, "cognitive.inter_command_latency_class").value == "instant"
+
+
+def test_typing_speed_bucket() -> None:
+    # IATs around 1.0s
+    starts = [i * 1.0 for i in range(6)]
+    out = list(extract_session(_command_stream(starts), sid="lat-typing"))
+    assert _of(out, "cognitive.inter_command_latency_class").value == "typing_speed"
+
+
+def test_deliberate_bucket() -> None:
+    # IATs around 1.85s — above typing (1.5), under deliberate cap (2.0)
+    starts = [i * 1.9 for i in range(6)]
+    out = list(extract_session(_command_stream(starts), sid="lat-deliberate"))
+    assert _of(out, "cognitive.inter_command_latency_class").value == "deliberate"
+
+
+def test_llm_lightweight_bucket() -> None:
+    # IATs around 5s — within 2-8s band
+    starts = [i * 5.05 for i in range(6)]
+    out = list(extract_session(_command_stream(starts), sid="lat-lwt"))
+    assert _of(out, "cognitive.inter_command_latency_class").value == "llm_lightweight"
+
+
+def test_llm_heavyweight_bucket() -> None:
+    # IATs around 15s — within 8-30s band; matches Claude Opus empirical
+    starts = [i * 15.05 for i in range(6)]
+    out = list(extract_session(_command_stream(starts), sid="lat-hvy"))
+    assert _of(out, "cognitive.inter_command_latency_class").value == "llm_heavyweight"
+
+
+def test_long_bucket() -> None:
+    # IATs > 30s
+    starts = [i * 60.0 for i in range(6)]
+    out = list(extract_session(_command_stream(starts), sid="lat-long"))
+    assert _of(out, "cognitive.inter_command_latency_class").value == "long"
+
+
+def test_low_sample_count_reduces_confidence() -> None:
+    # 2 commands → 1 IAT; below the floor
+    short = list(extract_session(_command_stream([0.0, 1.0]), sid="lat-low"))
+    full = list(extract_session(_command_stream([i * 1.0 for i in range(6)]), sid="lat-full"))
+    s = _of(short, "cognitive.inter_command_latency_class")
+    f = _of(full, "cognitive.inter_command_latency_class")
+    assert s.confidence < f.confidence