Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/microsoft/state-bench/custom-clientgit clone --depth 1 https://github.com/microsoft/STATE-BenchWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.01526 |
| Opus 5 | $0.00000 | $0.00763 |
| Sonnet 5 | $0.00000 | $0.00305 |
| Haiku 4.5 | $0.00000 | $0.00153 |
Grade A, and why
custom-client scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 175 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Custom Client + Agent
Use this path to evaluate models from a different provider or write a custom tool-calling agent. STATE-Bench does not ship third-party adapters — provider integration is user-owned.
Custom runs use two extension points together:
BaseLLMClient(state_bench/client.py) — your provider-specific client wrapper.BaseAgent(state_bench/agents/base.py) — your agent loop that calls that client and returns provider-neutral tool requests for the harness to execute.
File layout
Place your implementations under repo-root extension folders:
agents/
my_agent.py
clients/
my_client.py
Class names must be unique under their folder trees. The harness loads --agent-class from agents/ and --agent-client-class from clients/.
Provider environment variables
STATE-Bench does not interpret provider env vars; your BaseLLMClient.from_env() does. Add whatever your provider needs to .env:
MY_PROVIDER_API_KEY="<your provider api key>"
MY_PROVIDER_MODEL="<your model name>"
Custom client
Subclass BaseLLMClient and implement from_env(). The base class does not require a specific method shape; your custom agent decides which client methods to call.
# clients/my_client.py
import os
from state_bench.client import BaseLLMClient
class MyLLMClient(BaseLLMClient):
def __init__(self, api_key: str, model: str):
self.api_key = api_key
self.model = model
@classmethod
def from_env(cls):
return cls(
api_key=os.environ["MY_PROVIDER_API_KEY"],
model=os.environ.get("MY_PROVIDER_MODEL", "my-model"),
)
@property
def model_name(self):
return self.model
def generate(self, *, system_prompt, conversation, tools):
# Call your provider here. Convert STATE-Bench tool schemas to your
# provider's format if needed, and return an object your agent understands.
raise NotImplementedError
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 175 lines · 0 tokens per session scan A 3052aa99d4f4
custom-client is an agent published in the GitHub repository microsoft/STATE-Bench (82 stars, last pushed 27d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,526 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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