diff --git a/boss/SKILL.md b/boss/SKILL.md
index 09c0bf4..d73449f 100644
--- a/boss/SKILL.md
+++ b/boss/SKILL.md
@@ -93,6 +93,8 @@ brainstorm → planner → implement → audit → fieldtest
                   +
                   debug (bug-triggered)
                   +
+                  tdd → implement (mini)  (test-specifiable feature, if profile enables it)
+                  +
                   docwriter (post-stability)
 ```
 
@@ -105,6 +107,21 @@ does `brainstorm` get dispatched. If a spec exists but no plan:
 `audit`. If the iteration is a bug-fix: `debug`. Read each
 skill's `SKILL.md` trigger section if unsure.
 
+If the project profile enables the `tdd` phase and the picked
+item is a **test-specifiable feature issue** — its body pins one
+observable behaviour and the existing-cycle/new-cycle question
+does not apply (it is a backlog issue, not a top-level work
+container needing a fresh spec) — dispatch `tdd` autonomously,
+the same way a bug issue is dispatched to `debug`. `tdd` is its
+sibling: it authors a RED executable-spec and hands the GREEN
+side to `implement` mini-mode. This is **not** a new-cycle
+bounce-back (the test is the spec; no `brainstorm` is dispatched
+to begin). The bounce-back fires only reactively: if `tdd`
+reports the behaviour is not test-specifiable (a genuine design
+fork), that escalation routes to `brainstorm` and — being a new
+cycle that needs a fresh spec — is a bounce-back to the user per
+§"Direction freedom" trigger 4.
+
 If the working tree is mid-flight (uncommitted changes left over
 from a previous session): inspect first, then resume the right
 step. Do not restart from scratch.
@@ -299,4 +316,5 @@ actionable ask, not a wrap-up summary.
   record-reality discipline for the only autonomous glossary writer.
 - **Downstream skills dispatched:** `../brainstorm`,
   `../planner`, `../implement`, `../audit`, `../fieldtest`,
-  `../debug`, `../docwriter`.
+  `../debug`, `../tdd` (test-specifiable feature, profile-gated;
+  autonomously dispatchable like `../debug`), `../docwriter`.
diff --git a/brainstorm/SKILL.md b/brainstorm/SKILL.md
index 20b4bcd..40460e1 100644
--- a/brainstorm/SKILL.md
+++ b/brainstorm/SKILL.md
@@ -31,6 +31,12 @@ Triggers:
 **Skipping is permitted only** for:
 
 - A bug-fix iteration (use `debug` directly).
+- A test-specifiable feature, on a project whose profile
+  enables the `tdd` phase (use `tdd` directly — the RED
+  executable-spec is the spec, no prose spec needed). The
+  boundary is the design line: the moment one honest minimal
+  assertion cannot pin the behaviour without choosing between
+  plausible designs, `tdd` bounces back here.
 - A tidy iteration (use `audit` directly).
 - A trivial mechanical edit (per the project's CLAUDE.md
   "trivial mechanical edits" carve-out).
@@ -408,6 +414,12 @@ Hand off carries:
 
 - **Output target:** `../planner/SKILL.md` — only valid next
   skill.
+- **Alternative entry path / bounce-back source:**
+  `../tdd/SKILL.md` — on profiles that enable it, a
+  test-specifiable feature enters through `tdd` instead of
+  here; `tdd` bounces the work back to `brainstorm` the moment
+  the behaviour stops being test-specifiable (a genuine design
+  fork). Such a bounce-back arrives as a normal cycle request.
 - **Agent dispatched:** `agents/grounding-check.md` —
   dispatched in Step 7.5 as a hard-gate. The agent reads the
   spec with fresh context and reports PASS / BLOCK /
diff --git a/debug/SKILL.md b/debug/SKILL.md
index 5381558..9e7c7b8 100644
--- a/debug/SKILL.md
+++ b/debug/SKILL.md
@@ -40,6 +40,12 @@ Trigger this skill on:
 change, not a fix. Ad-hoc judgement that a bug is "too small
 for TDD" is the exact failure mode this skill exists to prevent.
 
+`debug` is for a regression of *existing* behaviour. New
+test-specifiable behaviour is its sibling `tdd`'s job (same
+two-stage RED→GREEN shape, triggered by a feature description
+rather than an observed misbehaviour) — route there instead,
+on profiles that enable it.
+
 ## The Iron Law
 
 ```
@@ -93,3 +99,7 @@ separate one.
   GREEN side after the orchestrator has decided whether to
   commit the RED test separately or as part of the final fix
   commit.
+- **Sibling RED-first skill:** `../tdd/SKILL.md` — same
+  two-stage RED→GREEN handoff to `implement` mini-mode, but
+  triggered by a new test-specifiable behaviour rather than an
+  observed bug.
diff --git a/implement/SKILL.md b/implement/SKILL.md
index 43ece8e..7af534f 100644
--- a/implement/SKILL.md
+++ b/implement/SKILL.md
@@ -35,8 +35,8 @@ orchestrator-agent every dispatch.
 Triggers:
 
 - A plan exists under `paths.plan_dir` (standard mode).
-- A `debug` skill has produced a RED test + cause and is
-  handing off for the GREEN side (mini mode).
+- A `debug` skill (RED test + cause) or a `tdd` skill (RED
+  executable-spec) has handed off for the GREEN side (mini mode).
 
 **Never skipped** when there is code to ship. Trivial
 mechanical edits (one-line typo fix, schema rename across N
@@ -91,15 +91,15 @@ Agent("implement-orchestrator", {
 })
 ```
 
-For a debug-handoff (mini mode):
+For a RED-first handoff from `debug` or `tdd` (mini mode):
 
 ```
 Agent("implement-orchestrator", {
   mode: "mini",
-  iter_id: "bugfix-<short-symptom>",
+  iter_id: "bugfix-<short-symptom>",   # tdd: "feat-<short-behaviour>"
   red_test_path: "<absolute path>",
-  cause_summary: "<1-2 sentences from debugger>",
-  constraint: "minimal fix, no surrounding cleanup"
+  cause_summary: "<1-2 sentences from debugger>",   # tdd: spec_summary, the desired-behaviour line
+  constraint: "minimal fix, no surrounding cleanup"   # tdd: "minimal feature, no surrounding scope"
 })
 ```
 
diff --git a/implement/agents/implement-orchestrator.md b/implement/agents/implement-orchestrator.md
index 39512ef..f03e3ae 100644
--- a/implement/agents/implement-orchestrator.md
+++ b/implement/agents/implement-orchestrator.md
@@ -125,7 +125,7 @@ ON `PARTIAL` OR `BLOCKED`, WRITE `BLOCKED.md` AT THE REPO ROOT BEFORE RETURNING.
   ```
   Make this RED test pass: <red_test_path>
 
-  Cause (from debugger):
+  Context (from debugger cause, or tdd spec_summary):
   <cause_summary>
 
   Constraint: <constraint>
@@ -258,8 +258,8 @@ E2E fixtures. Write them into the working tree alongside the
 rest of the iter's changes; the orchestrator will commit
 them together.
 
-(Mini mode: skip Phase 3 — the RED test from `debug` IS the
-coverage.)
+(Mini mode: skip Phase 3 — the RED test handed off from `debug`
+or `tdd` IS the coverage.)
 
 ### Phase 4 — On PARTIAL/BLOCKED, write BLOCKED.md
 
diff --git a/planner/SKILL.md b/planner/SKILL.md
index 0637d7b..b3ab834 100644
--- a/planner/SKILL.md
+++ b/planner/SKILL.md
@@ -36,6 +36,10 @@ May be skipped when:
 
 - The work is a bug fix where the RED test from `debug` IS
   the plan (handoff goes straight to `implement` mini-mode).
+- The work is a test-specifiable feature routed through `tdd`,
+  where the RED executable-spec IS the plan (handoff goes
+  straight to `implement` mini-mode). `tdd` skips both
+  `brainstorm` and `planner`.
 - The work is a trivial mechanical edit (per the project's
   CLAUDE.md "trivial mechanical edits" carve-out).