0edb6b928a
A delegated child copies the parent's prompt_caching.cache_ttl. The 1h tier is priced for a person who steps away between turns (2x write vs 1.25x for 5m); a subagent calls every few seconds for minutes and is gone, so it paid 2x on every tool result and never collected the retention. Live measurement (Sep 5, 40 concurrent Fable 5.1 children via OpenRouter, 1h markers on the wire): cache writes billed at $20/M against $12.51/M for the same run at 5m, ~60% of a write-dominated bill. _apply_child_cache_ttl runs right after child construction: 1h -> 5m, 5m stays, disabled stays disabled, parent untouched. Tests: unit (markers on the wire drop ttl; parent's 1h layout still differs) and the real spawn path with cache_ttl: 1h in a temp HERMES_HOME.
65 lines
3.1 KiB
Python
65 lines
3.1 KiB
Python
"""Subagents never inherit the 1h prompt-cache tier: with ``prompt_caching.cache_ttl: 1h`` the parent
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keeps 1h, the child is built at 5m, and the child's wire markers carry no ``ttl``. A disabled cache
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stays disabled (the child is not re-enabled to 5m)."""
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from types import SimpleNamespace
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from agent.prompt_caching import apply_anthropic_cache_control
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from tools.delegate_tool import _apply_child_cache_ttl
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def _markers(messages):
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out = []
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for m in messages:
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c = m.get("content")
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if isinstance(c, list):
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out += [b["cache_control"] for b in c if isinstance(b, dict) and "cache_control" in b]
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if "cache_control" in m:
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out.append(m["cache_control"])
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return out
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def test_child_1h_becomes_5m_and_wire_markers_drop_ttl():
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child = SimpleNamespace(_cache_ttl="1h")
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_apply_child_cache_ttl(child)
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assert child._cache_ttl == "5m"
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msgs = [{"role": "system", "content": "sys"}, {"role": "user", "content": "hi"},
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{"role": "assistant", "content": "ok"}, {"role": "user", "content": "go"}]
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wire = apply_anthropic_cache_control([dict(m) for m in msgs], cache_ttl=child._cache_ttl)
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marks = _markers(wire)
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assert marks and all("ttl" not in m for m in marks), marks
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# and the parent's 1h layout really is different, so this is not a vacuous check
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parent_marks = _markers(apply_anthropic_cache_control([dict(m) for m in msgs], cache_ttl="1h"))
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assert any(m.get("ttl") == "1h" for m in parent_marks)
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def test_disabled_and_5m_are_left_alone():
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for ttl in (None, "5m"):
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child = SimpleNamespace(_cache_ttl=ttl)
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_apply_child_cache_ttl(child)
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assert child._cache_ttl == ttl
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def test_real_spawn_path_applies_it(tmp_path, monkeypatch):
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"""Through ``_build_child_agent`` with a real AIAgent: parent configured 1h, child ends at 5m, and the
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parent is untouched."""
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monkeypatch.setenv("HERMES_HOME", str(tmp_path))
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(tmp_path / "config.yaml").write_text(
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"prompt_caching:\n cache_ttl: 1h\nmodel:\n default: anthropic/claude-sonnet-4.6\n", encoding="utf-8")
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from run_agent import AIAgent
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from tools import delegate_tool as dt
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import tools.delegate_tool_config as dtc
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monkeypatch.setattr(dt, "_load_config", lambda: {})
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monkeypatch.setattr(dtc, "_load_config", lambda: {})
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kw = dict(api_key="k", base_url="https://openrouter.ai/api/v1", provider="openrouter",
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api_mode="chat_completions", model="anthropic/claude-sonnet-4.6", platform="cli", quiet_mode=True,
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skip_context_files=True, skip_memory=True, save_trajectories=False, enabled_toolsets=["file"])
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parent = AIAgent(session_id="p", **kw)
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assert parent._cache_ttl == "1h", "fixture: the operator's 1h must actually be in effect"
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child = dt._build_child_agent(task_index=0, goal="goal", context=None, toolsets=["file"], model=None,
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max_iterations=4, task_count=1, parent_agent=parent)
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try:
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assert child._cache_ttl == "5m"
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assert parent._cache_ttl == "1h"
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finally:
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child.close()
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parent.close()
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