diff --git a/R/subagent.R b/R/subagent.R
index 78a0d98..1a5d301 100644
--- a/R/subagent.R
+++ b/R/subagent.R
@@ -96,9 +96,13 @@ resolve_subagent_id <- function(input) {
 #'
 #' Called once per child just after [worker_init()]. Creates a
 #' `new_session()` configured with the subagent's provider/model/tools
-#' and stores it where [subagent_turn_prompt()] can find it. Subagents
-#' deny all tool approvals by default so a subagent can't run bash
-#' without the parent opting in.
+#' and stores it where [subagent_turn_prompt()] can find it. The
+#' child's `approval_cb` denies by default: subagents have no
+#' interactive approval channel back to the parent or user, and tool
+#' permissions are fixed at spawn time via `tools_filter` (derived
+#' from the parent's `preset` or explicit `tools` argument to
+#' [subagent_spawn()]). There is no way to grant additional capability
+#' mid-run.
 #'
 #' @param provider LLM provider name (see [new_session()]).
 #' @param model Optional model override.
@@ -325,14 +329,27 @@ subagent_session_key <- function(parent_key) {
 #' registry set up. Stores the handle in the package-level registry
 #' keyed by subagent id.
 #'
+#' Permissions: subagents have no interactive approval channel back
+#' to the parent or user. The child's `approval_cb` denies by default
+#' and there is no mid-run escalation path. Whatever capability the
+#' child needs must be granted at spawn time through `preset` or
+#' `tools`. If a task may need shell, write, or network capability,
+#' pick a preset that includes it (or pass an explicit `tools` list);
+#' otherwise the child should report that it is blocked rather than
+#' retry.
+#'
 #' @param task Task description (stored for bookkeeping; not yet fed
 #'   into an agent loop).
 #' @param model Optional model override (reserved for later use).
 #' @param tools Optional explicit tool filter (character vector).
-#'   Overrides `preset` when provided.
-#' @param preset Preset name: `"investigate"` (read/search only, default),
-#'   `"work"` (investigate + bash + write/edit), or `"minimal"`
-#'   (read_file + grep_files only).
+#'   Overrides `preset` when provided. Fixed for the lifetime of the
+#'   child — cannot be expanded after spawn.
+#' @param preset Preset name (fixed for the lifetime of the child).
+#'   `"investigate"` (default): `read_file`, `grep_files`, `r_help`,
+#'   `web_search`, `fetch_url`. `"work"`: investigate + `bash`,
+#'   `write_file`, `replace_in_file`, `list_files`, `git_status`,
+#'   `git_diff`, `git_log`, `run_r`. `"minimal"`: `read_file`,
+#'   `grep_files`.
 #' @param parent_session Parent session object; read for
 #'   nested-spawning control and session-key derivation.
 #' @param config Config list.
diff --git a/man/subagent_spawn.Rd b/man/subagent_spawn.Rd
index 21a0bb9..e629890 100644
--- a/man/subagent_spawn.Rd
+++ b/man/subagent_spawn.Rd
@@ -13,11 +13,15 @@ into an agent loop).}
 \item{model}{Optional model override (reserved for later use).}
 
 \item{tools}{Optional explicit tool filter (character vector).
-Overrides `preset` when provided.}
+Overrides `preset` when provided. Fixed for the lifetime of the
+child — cannot be expanded after spawn.}
 
-\item{preset}{Preset name: `"investigate"` (read/search only, default),
-`"work"` (investigate + bash + write/edit), or `"minimal"`
-(read_file + grep_files only).}
+\item{preset}{Preset name (fixed for the lifetime of the child).
+`"investigate"` (default): `read_file`, `grep_files`, `r_help`,
+`web_search`, `fetch_url`. `"work"`: investigate + `bash`,
+`write_file`, `replace_in_file`, `list_files`, `git_status`,
+`git_diff`, `git_log`, `run_r`. `"minimal"`: `read_file`,
+`grep_files`.}
 
 \item{parent_session}{Parent session object; read for
 nested-spawning control and session-key derivation.}
@@ -31,4 +35,12 @@ Subagent ID (character).
 Starts a fresh `callr::r_session` with corteza loaded and its tool
 registry set up. Stores the handle in the package-level registry
 keyed by subagent id.
+Permissions: subagents have no interactive approval channel back
+to the parent or user. The child's `approval_cb` denies by default
+and there is no mid-run escalation path. Whatever capability the
+child needs must be granted at spawn time through `preset` or
+`tools`. If a task may need shell, write, or network capability,
+pick a preset that includes it (or pass an explicit `tools` list);
+otherwise the child should report that it is blocked rather than
+retry.
 }
diff --git a/man/subagent_turn_init.Rd b/man/subagent_turn_init.Rd
index b3b0fc4..bb306ec 100644
--- a/man/subagent_turn_init.Rd
+++ b/man/subagent_turn_init.Rd
@@ -29,8 +29,12 @@ Invisible TRUE.
 \description{
 Called once per child just after [worker_init()]. Creates a
 `new_session()` configured with the subagent's provider/model/tools
-and stores it where [subagent_turn_prompt()] can find it. Subagents
-deny all tool approvals by default so a subagent can't run bash
-without the parent opting in.
+and stores it where [subagent_turn_prompt()] can find it. The
+child's `approval_cb` denies by default: subagents have no
+interactive approval channel back to the parent or user, and tool
+permissions are fixed at spawn time via `tools_filter` (derived
+from the parent's `preset` or explicit `tools` argument to
+[subagent_spawn()]). There is no way to grant additional capability
+mid-run.
 }
 \keyword{internal}
diff --git a/vignettes/configuration.Rmd b/vignettes/configuration.Rmd
index 57c6095..6679227 100644
--- a/vignettes/configuration.Rmd
+++ b/vignettes/configuration.Rmd
@@ -125,9 +125,19 @@ All keys shown with type and default, current as of corteza 0.6.3. Most defaults
 | `subagents.max_concurrent` | integer | `3` | Max parallel subagents |
 | `subagents.timeout_minutes` | integer | `30` | Subagent kill timeout |
 | `subagents.allow_nested` | boolean | `false` | Allow nested subagents |
-| `subagents.default_tools` | string[] | `["base::readLines", "base::writeLines", "bash", "grep_files"]` | Tools available to subagents |
+| `subagents.default_tools` | string[] | `["read_file", "grep_files", "r_help", "web_search", "fetch_url"]` | Tools available to subagents when no preset is given |
 | `subagents.base_port` | integer | `7851` | Starting port for subagent MCP servers |
 
+**Presets.** `/spawn --preset <name>` picks a fixed tool list at spawn time:
+
+- `investigate` (default): `read_file`, `grep_files`, `r_help`, `web_search`, `fetch_url` (read/search/help, plus network reads).
+- `minimal`: `read_file`, `grep_files`.
+- `work`: investigate + `bash`, `write_file`, `replace_in_file`, `list_files`, `git_status`, `git_diff`, `git_log`, `run_r`.
+
+`/spawn --tools <comma-list>` overrides the preset with an explicit tool list.
+
+**Permission model.** Subagents have no interactive approval channel back to the parent or user. A child's tool list is fixed at spawn time — via the `--preset` or `--tools` flags on `/spawn`, or the `preset` / `tools` arguments to `subagent_spawn()`. There is no mid-run path to escalate to a riskier capability: the child's approval callback denies by default, and the parent cannot grant new tools after the fact. If a task may need shell, write, or network capability, choose a preset or explicit tool list that includes it at spawn time; otherwise the child should report that it is blocked.
+
 ### Workspace
 
 | Key | Type | Default | Description |
diff --git a/vignettes/retroactive-extraction.Rmd b/vignettes/retroactive-extraction.Rmd
index e70da6f..812a962 100644
--- a/vignettes/retroactive-extraction.Rmd
+++ b/vignettes/retroactive-extraction.Rmd
@@ -105,6 +105,19 @@ The LLM uses normal tool selection to decide between
 `query_subagent(id, "what did you find at line 42?")` and
 `spawn_subagent("...")` for new work.
 
+## Permission model
+
+Holder subagents (the ones the archival runtime creates) carry
+`tools = character(0)`: they hold transcript context for
+`query_subagent`, nothing more. Worker subagents spawned via
+`spawn_subagent(task)` inherit only the tools the parent grants at
+spawn time. There is no interactive approval channel back to the
+parent or user, and no way to grant capability mid-run — the child's
+`approval_cb` denies by default. If a worker may need shell, write, or
+network capability, pick a preset or explicit tool list that includes
+it when calling `spawn_subagent()`; otherwise the child should report
+that it is blocked rather than retry.
+
 ## Recursion
 
 A subagent finishing its own query re-evaluates the same triggers