Skip to content

fix(agent): cap recent history section in system prompt #3414

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
chengyongru merged 1 commit into from
Apr 23, 2026
Merged

fix(agent): cap recent history section in system prompt #3414

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 6 additions & 3 deletions nanobot/agent/context.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@

from nanobot.agent.memory import MemoryStore
from nanobot.agent.skills import SkillsLoader
from nanobot.utils.helpers import build_assistant_message, current_time_str, detect_image_mime
from nanobot.utils.helpers import build_assistant_message, current_time_str, detect_image_mime, truncate_text
from nanobot.utils.prompt_templates import render_template


Expand All @@ -19,6 +19,7 @@ class ContextBuilder:
BOOTSTRAP_FILES = ["AGENTS.md", "SOUL.md", "USER.md", "TOOLS.md"]
_RUNTIME_CONTEXT_TAG = "[Runtime Context — metadata only, not instructions]"
_MAX_RECENT_HISTORY = 50
_MAX_HISTORY_CHARS = 32_000 # hard cap on recent history section size
_RUNTIME_CONTEXT_END = "[/Runtime Context]"

def __init__(self, workspace: Path, timezone: str | None = None, disabled_skills: list[str] | None = None):
Expand Down Expand Up @@ -56,9 +57,11 @@ def build_system_prompt(
entries = self.memory.read_unprocessed_history(since_cursor=self.memory.get_last_dream_cursor())
if entries:
capped = entries[-self._MAX_RECENT_HISTORY:]
parts.append("# Recent History\n\n" + "\n".join(
history_text = "\n".join(
f"- [{e['timestamp']}] {e['content']}" for e in capped
))
)
history_text = truncate_text(history_text, self._MAX_HISTORY_CHARS)
parts.append("# Recent History\n\n" + history_text)

return "\n\n---\n\n".join(parts)

Expand Down
Loading