After every Hermes agent run, I print a 10-line summary. Now I know exactly what happened.

from trace_summary import summarize_file

s = summarize_file("logs/run.jsonl")
print(s)

Events:        142
Errors:        3
Cost:          $0.0847
Tokens:        48,200 (in=32,100 out=16,100)
Duration:      183.4s
Lanes:         supervisor, worker-1, worker-2
Event kinds:   tool_call=89, llm_call=42, log=11
Tool calls:    web_search×45, read_file×28, arxiv_search×16

from trace_summary import summarize_trace

# After collecting events in memory
s = summarize_trace(events)
logger.info(
    "Run complete",
    extra={
        "cost_usd": s.total_cost_usd,
        "errors": s.error_count,
        "duration_s": s.duration_seconds,
    }
)

@dataclass
class TraceSummary:
    event_count: int
    error_count: int
    total_cost_usd: float
    total_tokens_in: int
    total_tokens_out: int
    first_ts: float | None
    last_ts: float | None
    duration_seconds: float | None
    tool_counts: dict[str, int]
    kind_counts: dict[str, int]
    lanes: set[str]

s = summarize_file("run.jsonl")

if s.error_count > 0:
    alert(f"{s.error_count} errors in agent run")

if s.total_cost_usd > 1.00:
    alert(f"Run cost ${s.total_cost_usd:.2f} — over $1 budget")

trace-summary run.jsonl

import logging
from trace_summary import summarize_trace

class HermesAgentLoop:
    def run(self, ...):
        events = []
        ...
        # collect events throughout the run
        ...
        s = summarize_trace(events)
        logging.info("Run complete:\n%s", s.render())
        if s.error_count > 0:
            raise RuntimeError(f"{s.error_count} tool errors — check trace")

pip install trace-summary