Agent: unify bootstrap truncation warning handling (#32769)

Merged via squash.

Prepared head SHA: 5d6d4ddfa6
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

docs/concepts/context.md

@@ -114,6 +114,8 @@ By default, OpenClaw injects a fixed set of workspace files (if present):
 
 Large files are truncated per-file using `agents.defaults.bootstrapMaxChars` (default `20000` chars). OpenClaw also enforces a total bootstrap injection cap across files with `agents.defaults.bootstrapTotalMaxChars` (default `150000` chars). `/context` shows **raw vs injected** sizes and whether truncation happened.
 
+When truncation occurs, the runtime can inject an in-prompt warning block under Project Context. Configure this with `agents.defaults.bootstrapPromptTruncationWarning` (`off`, `once`, `always`; default `once`).
+
 ## Skills: what’s injected vs loaded on-demand
 
 The system prompt includes a compact **skills list** (name + description + location). This list has real overhead.

docs/concepts/system-prompt.md

@@ -73,7 +73,10 @@ compaction.
 Large files are truncated with a marker. The max per-file size is controlled by
 `agents.defaults.bootstrapMaxChars` (default: 20000). Total injected bootstrap
 content across files is capped by `agents.defaults.bootstrapTotalMaxChars`
-(default: 150000). Missing files inject a short missing-file marker.
+(default: 150000). Missing files inject a short missing-file marker. When truncation
+occurs, OpenClaw can inject a warning block in Project Context; control this with
+`agents.defaults.bootstrapPromptTruncationWarning` (`off`, `once`, `always`;
+default: `once`).
 
 Sub-agent sessions only inject `AGENTS.md` and `TOOLS.md` (other bootstrap files
 are filtered out to keep the sub-agent context small).

docs/gateway/configuration-reference.md

@@ -801,6 +801,21 @@ Max total characters injected across all workspace bootstrap files. Default: `15
 }
 ```
 
+### `agents.defaults.bootstrapPromptTruncationWarning`
+
+Controls agent-visible warning text when bootstrap context is truncated.
+Default: `"once"`.
+
+- `"off"`: never inject warning text into the system prompt.
+- `"once"`: inject warning once per unique truncation signature (recommended).
+- `"always"`: inject warning on every run when truncation exists.
+
+```json5
+{
+  agents: { defaults: { bootstrapPromptTruncationWarning: "once" } }, // off | once | always
+}
+```
+
 ### `agents.defaults.imageMaxDimensionPx`
 
 Max pixel size for the longest image side in transcript/tool image blocks before provider calls.