diff --git a/strix/tools/agent_browser/README.md b/strix/tools/agent_browser/README.md
new file mode 100644
index 0000000..ebdfb3a
--- /dev/null
+++ b/strix/tools/agent_browser/README.md
@@ -0,0 +1,12 @@
+# agent-browser
+
+Browser automation CLI installed in the sandbox image. Driven by the agent
+through `exec_command` (not a function tool).
+
+- **Implementation:** sandbox CLI at
+  `/home/pentester/.npm-global/bin/agent-browser` — npm package
+  `agent-browser@0.26.0` (Vercel), driving Chromium directly.
+- **Strix config:** `containers/Dockerfile` sets `AGENT_BROWSER_*` env
+  (executable path, UA, launch args, screenshot dir).
+- **Skill:** `strix/skills/tooling/agent_browser.md` — **always-loaded**
+  into every agent prompt by `strix/agents/prompt.py:_resolve_skills`.
diff --git a/strix/tools/apply_patch/README.md b/strix/tools/apply_patch/README.md
new file mode 100644
index 0000000..6598b83
--- /dev/null
+++ b/strix/tools/apply_patch/README.md
@@ -0,0 +1,10 @@
+# apply_patch
+
+SDK-provided file patching tool — the agent's only first-class way to edit
+files in the sandbox. Surfaced to the model as `patch` (renamed via
+`_TOOL_NAME_OVERRIDES` in `strix/agents/factory.py`).
+
+- **Implementation:** `agents.sandbox.capabilities.tools.apply_patch_tool.ApplyPatchTool`
+  (upstream `agents` SDK)
+- **Wired in:** `strix/agents/factory.py` — added per-run via the SDK
+  `Filesystem` capability.
diff --git a/strix/tools/shell/README.md b/strix/tools/shell/README.md
new file mode 100644
index 0000000..204c925
--- /dev/null
+++ b/strix/tools/shell/README.md
@@ -0,0 +1,15 @@
+# shell — `exec_command` + `write_stdin`
+
+SDK-provided shell tools wired per-run from the sandbox session. Every CLI
+invocation the agent makes (nmap, ffuf, agent-browser, python3, …) goes
+through `exec_command`. `write_stdin` streams input to a still-running
+process started by an earlier `exec_command` (for interactive prompts).
+
+- **Implementation:** `agents.sandbox.capabilities.tools.shell_tool.ShellTool`
+  (in the upstream `agents` SDK)
+- **Wired in:** `strix/agents/factory.py` — added per-run via the SDK
+  `Shell` capability; `write_stdin` is wrapped to drop the SDK's `pid`
+  arg from the function schema.
+- **Sandbox env:** `http_proxy` / `https_proxy` route every shell child
+  through Caido; `AGENT_BROWSER_*`, `REQUESTS_CA_BUNDLE` etc. come from
+  `containers/Dockerfile`.
diff --git a/strix/tools/view_image/README.md b/strix/tools/view_image/README.md
new file mode 100644
index 0000000..3827206
--- /dev/null
+++ b/strix/tools/view_image/README.md
@@ -0,0 +1,17 @@
+# view_image
+
+SDK-provided tool that loads an image from the sandbox workspace and
+returns it as an image content block for vision-capable models.
+
+- **Implementation:** `agents.sandbox.capabilities.tools.view_image.ViewImageTool`
+  (upstream `agents` SDK)
+- **Wired in:** `strix/agents/factory.py` — added per-run via the SDK
+  `Filesystem` capability.
+- **Strix defaults:** screenshots default to
+  `/workspace/.agent-browser-screenshots/` via `AGENT_BROWSER_SCREENSHOT_DIR`
+  (set in `containers/Dockerfile`; dir is created at container start in
+  `containers/docker-entrypoint.sh`).
+- **Skill:** screenshot workflow lives in `strix/skills/tooling/agent_browser.md`.
+- **Recovery:** vision-not-supported model rejections are auto-recovered
+  via `strix.core.sessions.strip_latest_image_from_session`, invoked from
+  `strix/core/execution.py`.