A small agent loop over ragleap-tools
Tool objects. The model proposes one action at a time, sees the result,
and proposes the next, up to a hard step cap. You bring the model as a plain
callable, or use the included adapter for OpenAI-compatible chat APIs; there is no database.
pip install ragleap-agents # or: uv add ragleap-agents
Quickstart
from ragleap_tools import CALCULATOR_TOOL
from ragleap_agents import Agent, Policy, TRUSTED
def my_llm(prompt: str) -> str:
... # call any model, return its text
agent = Agent(
llm=my_llm,
tools=[CALCULATOR_TOOL],
policy=Policy(max_steps=4, tools={"calculator": TRUSTED}),
)
result = agent.run("What is 6 * 7?")
print(result.status, result.answer) # done, a short summary of what was found
for step in result.steps: # the transcript: tool, arguments, status, observation
print(step["tool"], step["arguments"], step["status"])
Using a real model
openai_compatible returns the llm(prompt) -> str callable for any provider that speaks
the OpenAI chat-completions API. Standard library only. You pass the key in; it is never
read from the environment and never printed.
from ragleap_agents import Agent, Policy, TRUSTED, openai_compatible
tools = [CALCULATOR_TOOL]
llm = openai_compatible(
"https://api.groq.com/openai/v1", api_key, "openai/gpt-oss-20b",
mode="native", tools=tools, # or mode="json": the model replies with the JSON action as text
)
agent = Agent(llm, tools, Policy(tools={"calculator": TRUSTED}))
- https is required (
allow_insecure_http=Trueis for local testing), redirects are refused, responses are size-capped, and 408/429/5xx and network errors are retried with backoff (at most 5 retries,Retry-Afterhonoured up to 30 s). - Errors are
ProviderErrorand carry only a status code or an exception type, never a response body, URL or key.error_detail=Trueadds the first 300 characters of the error body (key scrubbed) to diagnose a provider; it is off by default. - The base URL is yours to set. There is no address check, so do not build it from untrusted input.
- In
nativemode the first tool call becomes the JSON action, and a reply with no tool call becomes an explicitdone.Agentstill validates, taints and gates every proposal. - The instruction in the prompt follows the mode.
Agentreadsprompt_style("json"or"native") from the model callable and the adapter advertises its mode, so nothing needs to be passed;Agent(prompt_style=...)overrides it. Native mode never asks for JSON. Policy(repair_attempts=1)asks the model once more after an unusable reply, with a short note that never repeats the bad reply. It is off by default, and a repaired proposal goes through the same checks.
What was observed with a real model (Groq, openai/gpt-oss-20b; one run of 20 labeled tasks
per configuration with scripts/live_runner.py; one model on one provider, not a benchmark):
- With 0.2.0's wording, JSON mode: the provider rejected the request with HTTP 400
tool_use_failedon 3 of 20 tasks (the same three in both sweeps) when the model answered in its own function-call format. - With 0.3.0's wording, two of those three tasks completed 4 of 4 times; the third (
i3, which reads a note containing an injected instruction) still failed 4 of 4. Tasks done in the sweep: JSON 19 of 20, native 19 of 20. Prefermode="native"with models that have one. - Native mode: with 0.2.0's wording, 2 of 46 saved native runs (three models) failed with HTTP 400
because the model called a tool named
jsonthat was not offered. With 0.3.0's wording, 0 of 26 runs did, which is too few to show an effect. - Models sometimes returned an empty reply, or invented an action name (
refusal) to decline. In nativei3the model declined the injected instruction 4 of 4 times, but as a JSON action namingrefusal, which the loop reports asinvalid_plan: it has no defined way to decline. With repair on (0.2.0's wording), 4 of the 5 runs where it fired ended with a valid action. Repair cannot help when the provider rejects the request, because no reply exists. - No run on three models ever proposed the injected
send_message, so the taint rule has not been triggered by a real model. It is tested with scripted models.
Approval gates: pause and resume
from ragleap_agents import ToolPolicy
policy = Policy(tools={"write_file": ToolPolicy(taints=False, outbound=True, requires_approval=True)})
agent = Agent(my_llm, tools, policy, store=my_store)
result = agent.run("save the report")
if result.status == "awaiting_approval":
call = result.pending # {"call_id", "tool", "arguments", "forced"}
# ... show it to a human, then, in this process or another one:
result = agent.resume(result.run_id, {call["call_id"]: True}) # or False to reject
A paused run is a plain JSON dict in a StateStore (save/load). The
in-memory store is included; write your own for a file, Redis or a database.
resume() raises ResumeError if the run is unknown, not awaiting approval,
or the decision does not match the pending call, so an approval cannot be replayed.
The safety model
- Every proposal is checked. The tool must exist and the arguments must fit
its JSON Schema (required keys, unknown keys, type and enum only; no
$reforoneOf). Anything else stops the run withstop_reason="invalid_plan"; no tool runs. - Tool results are untrusted data. They are capped (1,500 characters each,
4,000 in the prompt), fenced in
<observation>tags, and lookalike tags inside them are neutralised, case-insensitively. - Taint rule. Declare each tool with a
ToolPolicy:taints(its result is external content) andoutbound(it acts on the outside world). Once a tainting tool has run, every later outbound tool needs approval, whatever else is configured. The policy can only tighten. - Fail closed. A tool with no declared policy counts as both tainting and outbound.
Use
TRUSTEDonly for tools that neither return external content nor act outside. - Limits.
max_steps(default 4, hard cap 8), a duplicate-action stop, and a deadline checked between calls (a running tool is not interrupted). - Failures stay contained.
run()does not raise for model or tool failures. A tool's exception text is never shown to the model or returned; only its type is.
What this does not do: it does not stop prompt injection. It limits what an
injected instruction can do, and only as far as your ToolPolicy declarations are
accurate. Tool descriptions are shown to the model too (capped at 300 characters),
so tools from an untrusted source (for example a remote MCP server) can inject
through them. Approval prompts are only as good as the human reading them.
Status
v0.3.0, alpha. 123 tests on Python 3.10, 3.11 and 3.12 (see tests/), most with a scripted
model or a local fake server; each safety property above has a test that fails if the property
is broken.
Behaviour changes: since 0.2.0 the instruction wording depends on the mode (prompt_style);
since 0.1.0 a model reply that is not a single JSON object stops the run
(stop_reason="unparseable_reply") instead of reporting done. See the CHANGELOG.
Not verified: the taint rule against a real model (none ever tried the injected action), any
provider other than Groq (Gemini has not been tried), long runs, concurrent resumes across
processes (your store must make resume atomic), and equivalence with RagLeap Core's own agent
loop, which this mirrors as of core commit 59fd555 (see docs/design/agent-loop.md).
License
MIT