inspect-robots-agent 0.15.0

LLM agent policy for Inspect Robots: frontier LLMs (Claude, GPT, anything OpenAI-compatible) drive any registered embodiment through tool calls.

inspect-robots-agent

LLM agent policy for Inspect Robots: frontier LLMs (Claude, GPT, anything behind an OpenAI-compatible API) drive any registered embodiment through tool calls, as a first-class Policy named agent. The same policy runs ad-hoc instructions and scores on registered tasks next to fine-tuned VLAs.

Install

pip install inspect-robots inspect-robots-agent

Quickstart (no hardware)

export ANTHROPIC_API_KEY=sk-ant-...

inspect-robots "pick up the cube" --policy agent \
    -P model=anthropic/claude-fable-5 -P effort=low --embodiment cubepick

Model strings are OpenRouter-style provider/model, resolved from -P model=... or $INSPECT_ROBOTS_MODEL. API keys come from the environment:

1. -P base_url=... (with -P api_key_env=NAME): any OpenAI-compatible endpoint
2. A known provider prefix with that provider's key set: the provider's own endpoint, prefix stripped from the model id
3. OPENROUTER_API_KEY: OpenRouter, any model string. Ids ending in a known OpenRouter variant suffix (:free, :nitro, :floor, :extended, :online, :thinking) always route here, since the variant means nothing to a provider's own API; other colons (fine-tune ids like openai/ft:...) still resolve directly.

Providers resolved directly by prefix:

Prefix	Key	Endpoint
anthropic/*	ANTHROPIC_API_KEY	Anthropic (OpenAI-compat, or native with -P wire=anthropic)
openai/*	OPENAI_API_KEY	OpenAI
google/*	GEMINI_API_KEY	Google Gemini (OpenAI-compat)
x-ai/* or xai/*	XAI_API_KEY	xAI
groq/*	GROQ_API_KEY	Groq (rest of the id passed through, slashes and all)
mistralai/*	MISTRAL_API_KEY	Mistral
deepseek/*	DEEPSEEK_API_KEY	DeepSeek

The wire format defaults to Chat Completions for broad OpenAI-compatible endpoint support:

-P wire=	Endpoint	Use it when
chat (default)	/chat/completions	Anything OpenAI-compatible: OpenRouter, vLLM, Ollama, the Anthropic and Gemini compat endpoints
responses	/responses	A direct OpenAI or compatible endpoint requires the Responses API
anthropic	/messages	Driving Claude natively, which is what fast mode needs

How it works

Motion tool calls state where to go, not how long to move. For absolute modes, the move tool (move_joints for joint spaces, move_to for Cartesian pose modes) interpolates named partial targets from the observed state at a fixed safe speed. The default max_speed_frac=0.1 allows a tenth of each dimension's range per second, subject to a 5%-of-range per-step ceiling that matches the core's default delta backstop. At that default a near-full-range move exceeds the 10 s per-call playout cap, so the agent receives a split-the-move error and issues it as two smaller motions; raise the fraction (up to 0.5 before the ceiling binds at 10 Hz) for faster arms. The tool result reports the computed step count and, when the embodiment declares control_hz, the corresponding playout time. duration_s is not part of either motion tool.

Every move tool call also requires a note with one or two plain sentences describing the current observation and why the agent chose that motion. The user reads these notes live and in the saved transcript to follow what the agent sees and decides.

Camera images are attached to every observation by default (-P images=always). Set -P images=on_demand to send state without image payloads and give the model a take_pic tool instead:

inspect-robots "pick up the cube" --policy agent \
    -P model=anthropic/claude-fable-5 -P images=on_demand \
    --embodiment cubepick

take_pic requires a human-readable note and accepts an optional cameras list. Omitting the list requests every camera available in that observation. A camera can be revealed only once per observation because its view cannot change until the robot moves. If a runtime camera dropout leaves the observation with no images, the well-formed call is rejected with no camera images are available in this observation instead of counting as a malformed tool call. The first such world-state rejection in one policy decision is free; repeated rejections escalate to the normal three-strike guard.

A standalone take_pic shows the current frame and lets the model decide again before moving. A take_pic placed after one motion in the same assistant turn is queued with queued: frames arrive with the next observation, after the motion plays: the motion chunk is returned immediately, and the requested frames are attached to the next observation after the controller has played the available part of the chunk. Two motions still cannot be chained.

Queued-capture narration reports what the rollout actually observed. It says whether all requested chunk steps played or only a prefix did, names camera frames missing on arrival, and, for absolute control modes with matching proprioception, reports the largest measured offset from the requested target. The residual is the arrival check: a full step count alone does not prove the arm reached its target when an approver rewrote actions or a smoothing controller blended them.

Controller choice affects that report. DefaultController buffers min(replan_interval, chunk_len) actions, so a replan_interval shorter than the interpolation always reports partial playout; a chunk shorter than the interval reports finished. EnsemblingController re-queries every control step, so the observed advance is always one step. It also rebuilds actions from chunk metadata, which means done and give_up do not terminate under ensembling (an existing core limitation). A trial that terminates or reaches its step limit before the next policy call drops any queued capture.

For displacement modes, move_by splits the requested total so every action fits the box side in that direction. The action box is the embodiment author's per-step speed statement, so max_speed_frac does not apply to displacement modes. done and give_up end the trial through the core's policy-stop channel.

When control_hz is None, the plugin uses a 10 Hz fallback to compute step counts and the per-call playout cap, but leaves the emitted chunk rate unset. The embodiment then plays the chunk at its native rate. In this case the speed and playout caps are step-count constructs, not wall-clock guarantees, and the tool result does not report seconds.

When the embodiment publishes operating notes via EmbodimentInfo.docs (joint layout, sign conventions, gripper polarity), the policy appends them to the system prompt as an Embodiment notes: section. The per-step observation also labels the proprioceptive state vector with the action dimension names (left_j0=0.01 ...) whenever the mapping is unambiguous.

Every action still passes the CLI's default safety approvers (bounds clamp plus per-step delta limit); the plugin contains no safety-critical code path of its own. An explicit --max-action-delta tighter than 5% of range can truncate absolute interpolants. In displacement modes, a value tighter than the action box can truncate each move_by step. Either setting can make the executed motion fall short of the tool's requested total.

Warning: Guardrails are on by default at the CLI. Never pass --disable-guardrails on real hardware unless you fully trust the policy and the rig.

Configuration knobs (all -P key=value): model, base_url, api_key_env, wire, speed, max_output_tokens, max_llm_calls (default 100), temperature, effort, max_speed_frac, transcript_echo, images, and image_horizon. speed and max_output_tokens apply to -P wire=anthropic only, and passing either on another wire is an error rather than a silent no-op.

Image option	Default	Behavior
-P images=	always	Attach every observation's frames; use on_demand for model-requested frames
-P image_horizon=	2	Keep frames from the newest two image-bearing messages in each outgoing request

Set -P image_horizon=none to send the full image history. Do not use a bare -P image_horizon=: the CLI parses it as an empty string, which the policy rejects. Full history grows request bodies by about 420 KB per observation with three cameras and can reach a 413 response around 85 observations. The default replaces older outgoing camera parts with deterministic text stubs; the saved conversation, transcript, and separately stored frames remain complete and unchanged.

Set -P transcript_echo=true to print live [agent] conversation lines to stderr, including goals, observation summaries, assistant output, tool calls, and tool results. Move notes appear inside the echoed tool-call arguments. The speed fraction defaults to 0.1 and applies only to absolute modes.

LLMAgentPolicy.transcript() returns the current conversation as a deep copy with streamed camera frames replaced by omission markers, ready for core eval-log persistence. Camera labels such as camera 'top_cam' (step 480): provide the join key from a transcript observation to its stored frame. Live Rerun transcript streaming happens automatically when a Rerun sink is attached. At trial end, record.metadata["llm_usage"] records llm_calls and the summed integer token counters returned by the wire. The native Anthropic wire includes input, output, cache-creation, and cache-read tokens; other wires currently record llm_calls only. Trials with no LLM calls omit the key.

Reasoning effort defaults to low: robot control is latency-sensitive (the arm stands still while the model thinks), safety guardrails sit below the model either way, and frontier models at low effort remain strong at this task shape. Raise it for hard manipulation problems (-P effort=high) or pass -P effort=none to omit the parameter for endpoints that reject it (the CLI reads a bare none as null). To send the literal wire value none and disable reasoning, quote it: -P effort="'none'". GPT-5.x on chat completions requires the literal none when function tools are in play (any other value, or omitting the field, is a 400). In Python, effort=None omits the field and effort="none" sends the wire value.

Fast mode on Claude

-P wire=anthropic drives Claude through the native Messages API instead of the OpenAI-compat endpoint. That is the only way to reach fast mode, which serves the same model at up to 2.5x higher output tokens per second:

inspect-robots "pick up the cube" --policy agent \
    -P model=anthropic/claude-opus-5 -P wire=anthropic -P speed=fast \
    --embodiment cubepick

The model id keeps the anthropic/ prefix on this wire, the same as every other model string here. Only Anthropic's own endpoint serves /v1/messages, so anything that resolves elsewhere is refused up front with the fix named: a bare -P model=claude-opus-5, another provider's prefix such as openai/, or an OpenRouter :variant suffix. Pass -P base_url=... to point at a gateway that serves the endpoint yourself.

Note: With -P base_url=... and no -P api_key_env=, this wire sends $ANTHROPIC_API_KEY to that host. The other wires default to $OPENROUTER_API_KEY instead. Name the variable explicitly (-P api_key_env=MYGW_KEY) when the gateway takes its own credential, and point it at an unset variable to send no key at all.

Fast mode costs roughly double the standard price on both input and output (see Anthropic's pricing), and it draws on a rate limit separate from standard capacity, so a fast-mode run can hit a 429 while standard quota sits idle. It is available on Claude Opus 5 and Opus 4.8, on the Claude API only: not Bedrock, Vertex, Foundry, or Claude Platform on AWS. A rejection that names fast mode is turned into an error naming the fix.

This wire always requests adaptive thinking, which pre-4.6 models such as Sonnet 4.5 and Haiku 4.5 do not support. Use -P wire=chat for those.

The Messages API requires an output cap, so -P max_output_tokens= defaults to 16000 here. Thinking bills against that same cap, and a response truncated at the limit is an error naming the knob rather than a silently missing tool call. Keep -P effort= at high or below on this wire: xhigh and max want a cap of 64000 or more, which needs streaming this client does not implement yet. The read timeout scales with the cap and tops out at 600 s per attempt, so a large cap plus retries can sit for several minutes before failing.

Prompt caching is automatic on this wire. Requests use up to three ephemeral breakpoints: the system prompt, the newest elided-image anchor when one exists, and the final message. Check record.metadata["llm_usage"]["cache_read_input_tokens"] to verify cache hits; it should become positive after the first ordinary call. Anthropic searches only 20 blocks behind a breakpoint, so a cycle with heavy retry or on-demand rejection churn can cause one silent full-prefix rewrite and a temporary zero cache-read count. A final nudge also changes wire shape once it is superseded. Both are cost blips rather than errors, and the anchor normally restores the hit on the next cycle.

Reasoning effort on OpenAI models

Recent OpenAI reasoning models can reject function tools on the Chat Completions wire with an error like this:

Function tools with reasoning_effort are not supported. To use function
tools, use /v1/responses or set reasoning_effort to 'none'.

This is a Chat Completions API restriction, not an inspect-robots bug. Use a direct OpenAI endpoint and select the Responses wire to keep reasoning enabled:

inspect-robots "pick up the cube" --policy agent \
    -P model=openai/gpt-5.6-sol -P wire=responses -P effort=medium \
    --embodiment cubepick