docs: align memory bootstrap docs (#12937) (thanks @omair445)

Address review feedback: the runtime also injects lowercase memory.md
(DEFAULT_MEMORY_ALT_FILENAME) when present.

docs/concepts/system-prompt.md

@@ -59,11 +59,24 @@ Bootstrap files are trimmed and appended under **Project Context** so the model
 - `USER.md`
 - `HEARTBEAT.md`
 - `BOOTSTRAP.md` (only on brand-new workspaces)
+- `MEMORY.md` and/or `memory.md` (when present in the workspace; either or both may be injected)
+
+All of these files are **injected into the context window** on every turn, which
+means they consume tokens. Keep them concise — especially `MEMORY.md`, which can
+grow over time and lead to unexpectedly high context usage and more frequent
+compaction.
+
+> **Note:** `memory/*.md` daily files are **not** injected automatically. They
+> are accessed on demand via the `memory_search` and `memory_get` tools, so they
+> do not count against the context window unless the model explicitly reads them.
 
 Large files are truncated with a marker. The max per-file size is controlled by
 `agents.defaults.bootstrapMaxChars` (default: 20000). Missing files inject a
 short missing-file marker.
 
+Sub-agent sessions only inject `AGENTS.md` and `TOOLS.md` (other bootstrap files
+are filtered out to keep the sub-agent context small).
+
 Internal hooks can intercept this step via `agent:bootstrap` to mutate or replace
 the injected bootstrap files (for example swapping `SOUL.md` for an alternate persona).
 

docs/reference/token-use.md

@@ -18,7 +18,7 @@ OpenClaw assembles its own system prompt on every run. It includes:
 - Tool list + short descriptions
 - Skills list (only metadata; instructions are loaded on demand with `read`)
 - Self-update instructions
-- Workspace + bootstrap files (`AGENTS.md`, `SOUL.md`, `TOOLS.md`, `IDENTITY.md`, `USER.md`, `HEARTBEAT.md`, `BOOTSTRAP.md` when new). Large files are truncated by `agents.defaults.bootstrapMaxChars` (default: 20000).
+- Workspace + bootstrap files (`AGENTS.md`, `SOUL.md`, `TOOLS.md`, `IDENTITY.md`, `USER.md`, `HEARTBEAT.md`, `BOOTSTRAP.md` when new, plus `MEMORY.md` and/or `memory.md` when present). Large files are truncated by `agents.defaults.bootstrapMaxChars` (default: 20000). `memory/*.md` files are on-demand via memory tools and are not auto-injected.
 - Time (UTC + user timezone)
 - Reply tags + heartbeat behavior
 - Runtime metadata (host/OS/model/thinking)