refactor: rebuild agent system prompt

docs/concepts/system-prompt.md

@@ -0,0 +1,64 @@
+---
+summary: "What the ClaudeBot system prompt contains and how it is assembled"
+read_when:
+  - Editing system prompt text, tools list, or time/heartbeat sections
+  - Changing workspace bootstrap or skills injection behavior
+---
+# System Prompt
+
+ClaudeBot builds a custom system prompt for every agent run. The prompt is **Clawdbot-owned** and does not use the p-coding-agent default prompt.
+
+The prompt is assembled in `src/agents/system-prompt.ts` and injected by `src/agents/pi-embedded-runner.ts`.
+
+## Structure
+
+The prompt is intentionally compact and uses fixed sections:
+
+- **Tooling**: current tool list + short descriptions.
+- **Skills**: tells the model how to load skill instructions on demand.
+- **ClaudeBot Self-Update**: how to run `config.apply` and `update.run`.
+- **Workspace**: working directory (`agent.workspace`).
+- **Workspace Files (injected)**: indicates bootstrap files are included below.
+- **Time**: UTC default + the user’s local time (already converted).
+- **Reply Tags**: optional reply tag syntax for supported providers.
+- **Heartbeats**: heartbeat prompt and ack behavior.
+- **Runtime**: host, OS, node, model, thinking level (one line).
+
+## Workspace bootstrap injection
+
+Bootstrap files are trimmed and appended under **Project Context** so the model sees identity and profile context without needing explicit reads:
+
+- `AGENTS.md`
+- `SOUL.md`
+- `TOOLS.md`
+- `IDENTITY.md`
+- `USER.md`
+- `HEARTBEAT.md`
+- `BOOTSTRAP.md` (only on brand-new workspaces)
+
+Large files are truncated with a marker. Missing files inject a short missing-file marker.
+
+## Time handling
+
+The Time line is compact and explicit:
+
+- Assume timestamps are **UTC** unless stated.
+- The listed **user time** is already converted to `agent.userTimezone` (if set).
+
+Use `agent.userTimezone` in `~/.clawdbot/clawdbot.json` to change the user time zone.
+
+## Skills
+
+Skills are **not** auto-injected. Instead, the prompt instructs the model to use `read` to load skill instructions on demand:
+
+```
+<workspace>/skills/<name>/SKILL.md
+```
+
+This keeps the base prompt small while still enabling targeted skill usage.
+
+## Code references
+
+- Prompt text: `src/agents/system-prompt.ts`
+- Prompt assembly + injection: `src/agents/pi-embedded-runner.ts`
+- Bootstrap trimming: `src/agents/pi-embedded-helpers.ts`

docs/docs.json

@@ -543,6 +543,7 @@
           "concepts/architecture",
           "concepts/agent",
           "concepts/agent-loop",
+          "concepts/system-prompt",
           "concepts/agent-workspace",
           "concepts/multi-agent",
           "concepts/compaction",