feat: refine subagents + add chat.inject

Co-authored-by: Tyler Yust <tyler6204@users.noreply.github.com>

src/agents/pi-embedded-runner/run/attempt.ts

@@ -12,6 +12,7 @@ import { getMachineDisplayName } from "../../../infra/machine-name.js";
 import { resolveTelegramReactionLevel } from "../../../telegram/reaction-level.js";
 import { normalizeMessageChannel } from "../../../utils/message-channel.js";
 import { isReasoningTagProvider } from "../../../utils/provider-utils.js";
+import { isSubagentSessionKey } from "../../../routing/session-key.js";
 import { resolveUserPath } from "../../../utils.js";
 import { resolveClawdbotAgentDir } from "../../agent-paths.js";
 import { resolveSessionAgentIds } from "../../agent-scope.js";
@@ -189,6 +190,7 @@ export async function runEmbeddedAttempt(
       config: params.config,
     });
     const isDefaultAgent = sessionAgentId === defaultAgentId;
+    const promptMode = isSubagentSessionKey(params.sessionKey) ? "minimal" : "full";
 
     const appendPrompt = buildEmbeddedSystemPrompt({
       workspaceDir: effectiveWorkspace,
@@ -202,6 +204,7 @@ export async function runEmbeddedAttempt(
         : undefined,
       skillsPrompt,
       reactionGuidance,
+      promptMode,
       runtimeInfo,
       sandboxInfo,
       tools,