Refresh README + ARCHITECTURE for the shipped feature set

ARCHITECTURE.md

@@ -6,7 +6,7 @@ it, an adapter performs the call, and the result is logged and returned. Everyth
 described in a plain editable config file — adding or removing a backend is a config edit, not a
 code change.
 
-This document describes the architecture as of **v0.9.0**. Per-change history lives in
+This document describes the architecture as of **v0.15.0**. Per-change history lives in
 [`CHANGELOG.md`](CHANGELOG.md); how to run it lives in [`README.md`](README.md); the opt-in /
 bring-your-own-key posture lives in [`DISCLAIMER.md`](DISCLAIMER.md).
 
@@ -149,15 +149,16 @@ extra (`pip install -e ".[delegate]"`). Four tools:
   orchestrator can also route explicitly by fit. The `delegate` tool's description enumerates the
   menu, built once at server startup.
 
-These are the first three slices of a [scatter-gather roadmap](https://github.com/Jason-Vaughan/TangleBrain/issues/39):
+These complete the [scatter-gather roadmap](https://github.com/Jason-Vaughan/TangleBrain/issues/39):
 the orchestrator routes a sub-task to any configured backend (by id or capability) and fans batches
 out concurrently. The **reduce step is deliberately not TangleBrain's** — the orchestrator synthesises
 the `delegate_many` results itself (it holds the original task context that makes for good synthesis),
 and offloads the stitch with an ordinary `delegate(task=…)` call when the reduction is mechanical and
 large. No dedicated reducer tool: the existing primitives cover it, and frontier-side synthesis is the
-better default until usage proves otherwise. Delegated sub-calls are now **metered** (see Measurement
-below) — the deferred observability landed as a by-backend breakdown; a per-parent-task tree (linking
-each delegation to its top-level task across processes) is the remaining stretch.
+better default until usage proves otherwise. Delegated sub-calls are **metered** (see Measurement
+below) as a by-backend breakdown, and each is **linked back to the specific top-level task that spawned
+it** across the process boundary (the per-parent-task tree, below) — so the roadmap is complete, not
+just core-complete.
 
 ### Measurement — per-task records (`measurement.py`)
 
@@ -176,9 +177,14 @@ each `delegate_many` item, is metered at that single seam). The rollup keeps del
 the headline** — the parent task already credits the whole job, so counting the sub-calls again would
 double-count the saving — and aggregates them **separately** into a by-backend breakdown (count, est
 tokens, informational cloud-equiv) surfaced in `--stats` and the GUI. Concurrent appends (delegate_many
-fans out across threads) are serialized by a process-level lock. Linking each delegation to its
-*specific* parent task across processes (a true tree) is deferred — it needs a task-id propagated
-through the orchestrator CLIs to the MCP child, which can't be verified hermetically.
+fans out across threads) are serialized by a process-level lock. Each delegation is also linked to its
+*specific* parent task across processes (a true tree): the CLI mints a `task_id` per routed task and
+injects it as `TANGLEBRAIN_TASK_ID` into the orchestrator's environment, the orchestrator forwards it
+to the MCP delegate child, and `run_delegate` reads it back to stamp each delegate record's
+`parent_task_id`. The rollup groups delegates `by_parent` (a "Linked to" tree in `--stats` and the
+GUI); a sub-call run outside a propagated task is `unlinked`. The orchestrator-forwards-env hop is
+verified live (claude), not hermetically — a delegation that loses the env degrades safely to
+`unlinked`, never an error.
 
 ### Knob GUI — localhost panel (`gui/`)
 

CHANGELOG.md

@@ -7,6 +7,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Internal
+
+- **Refreshed README + ARCHITECTURE for the shipped feature set.** The README status line is now
+  version-agnostic (links the latest release + CHANGELOG instead of a fixed version that drifts), and
+  the delegation bullet describes the full **scatter-gather** capability (route by id/capability, fan
+  out concurrently, metered + linked to the parent task) instead of the old local-only phrasing.
+  `ARCHITECTURE.md` is stamped v0.15.0 and its per-parent-task-tree passages — which still called the
+  tree "deferred" / "the remaining stretch" — now describe it as **shipped** (the `TANGLEBRAIN_TASK_ID`
+  propagation mechanism). Docs-only; no code change.
+
 ## [0.15.0] - 2026-06-18
 
 ### Added

README.md

@@ -40,7 +40,8 @@ and open to contributors: forks and pull requests are welcome. It's also designe
 seamlessly alongside [TangleClaw](https://github.com/Jason-Vaughan/TangleClaw) and the wider **Tangle
 family** of tools, so it works the same whether you run it solo or as part of that ecosystem.
 
-**Status:** v0.10.0 — first public release.
+**Status:** publicly released and actively developed — see the
+[latest release](https://github.com/Jason-Vaughan/TangleBrain/releases) and [`CHANGELOG.md`](CHANGELOG.md).
 
 ## What it does
 
@@ -56,8 +57,11 @@ family** of tools, so it works the same whether you run it solo or as part of th
   or reorganize backends by editing config.
 - **Pluggable CLI-backed orchestration** — drive authenticated command-line tools as orchestrators,
   with rotation and failover across them for resilience.
-- **Local sub-task delegation** — an orchestrator can offload bulk sub-tasks to the local backend
-  through an MCP tool, then review the results.
+- **Multi-target sub-task delegation (scatter-gather)** — an orchestrator can decompose a task and
+  offload sub-tasks through MCP tools: to the free local backend, or to any configured backend **by id
+  or by capability** (a `good_at` tag), and **fan several out concurrently** in one call. Each
+  delegated sub-call is metered and linked back to the specific top-level task that spawned it, then
+  the orchestrator reviews and synthesises the results.
 - **Cost measurement** — every routed task is logged with an estimated cloud-equivalent cost;
   `tanglebrain --stats` rolls up what you've spent versus avoided.
 - **Knob GUI** — a localhost panel to view the roster, pricing, and rollup, edit a focused set of