Ax for Rust API Reference

This generated API reference is emitted by AxIR from compiler-owned metadata. Do not edit it by hand; change the AxIR generator and regenerate packages instead.

Package

• Target: rust
• Package: axllm
• AxIR contract: 0.1

Signatures

Describe typed Ax inputs and outputs once, then reuse that shape for schemas, prompts, validation, tools, and structured results.

s

Parse an Ax string signature into the target language signature object.

• Canonical Ax concept: s
• Kind: function
• Form: s(spec: &str)
• Returns: AxResult<AxSignature>

let sig = s("question:string -> answer:string")?;

f

Build signatures and field types fluently when the target has a fluent helper.

• Canonical Ax concept: f
• Kind: function
• Form: f().input(...).output(...).build()
• Returns: signature builder or field factory
• Important options: input fields, output fields, field descriptions, constraints

AxSignature

Parsed signature with input/output fields, descriptions, and JSON schema helpers.

• Canonical Ax concept: AxSignature
• Kind: type
• Form: AxSignature
• Returns: signature object
• Important options: inputs, outputs, description

AxGen

Run structured generation with Core-owned prompts, tool loops, retries, streaming folds, traces, usage, examples, and field processors.

ax

Create an AxGen program from a string or parsed signature.

• Canonical Ax concept: ax
• Kind: function
• Form: ax(spec: &str)
• Returns: AxResult<AxGen>
• Important options: functions, examples, demos, modelConfig, maxRetries, streaming assertions, field processors

let qa = ax("question:string -> answer:string")?;

AxGen

Structured generation program with forward, streaming, optimization, trace, usage, and tool-call behavior.

• Canonical Ax concept: AxGen
• Kind: type
• Form: AxGen
• Returns: program object
• Important options: signature, functions, examples, demos, memory, prompt template

AxAI

Call supported providers through the shared provider descriptor registry, scripted transports, routers, and balancers.

ai

Create a provider client from a provider name and options.

• Canonical Ax concept: ai
• Kind: function
• Form: ai(provider, options)
• Returns: AxResult<OpenAICompatibleClient>
• Important options: api key, model, api URL, headers, transport

let client = ai("openai", json!({"apiKey": std::env::var("OPENAI_API_KEY")?}))?;

OpenAICompatibleClient

OpenAI-compatible chat, stream, embedding, audio, and realtime provider boundary.

• Canonical Ax concept: OpenAICompatibleClient
• Kind: type
• Form: OpenAICompatibleClient / ai(provider, options)
• Returns: provider client
• Important options: api key, model, base URL, transport

OpenAIResponsesClient

OpenAI Responses provider mapping using the same Core-owned request and response contract.

• Canonical Ax concept: OpenAIResponsesClient
• Kind: type
• Form: OpenAIResponsesClient / ai(provider, options)
• Returns: provider client
• Important options: api key, model, audio, realtime

GoogleGeminiClient

Gemini provider mapping for chat, streaming, media, tools, embeddings, and usage normalization.

• Canonical Ax concept: GoogleGeminiClient
• Kind: type
• Form: GoogleGeminiClient / ai(provider, options)
• Returns: provider client
• Important options: api key, model, embed model

AnthropicClient

Anthropic provider mapping for messages, thinking, cache control, streaming, and usage normalization.

• Canonical Ax concept: AnthropicClient
• Kind: type
• Form: AnthropicClient / ai(provider, options)
• Returns: provider client
• Important options: api key, model, thinking, cache control

AxUsageContext

Application attribution merged from service defaults and per-call overrides.

• Canonical Ax concept: AxUsageContext
• Kind: type
• Form: AxUsageContext
• Returns: usage context
• Important options: tenant, user, request, run, feature, attributes

AxUsageEvent

Normalized token usage and correlation data for one completed chat or embedding operation.

• Canonical Ax concept: AxUsageEvent
• Kind: type
• Form: AxUsageEvent
• Returns: usage event
• Important options: provider, model, tokens, context, correlation IDs, streaming

AxUsageObserver

Best-effort process-wide callback for normalized usage events.

• Canonical Ax concept: AxUsageObserver
• Kind: interface
• Form: AxUsageObserver
• Returns: usage observer
• Important options: fail-open delivery, synchronous enqueue

set_usage_observer

Register, replace, or clear the process-wide usage observer.

• Canonical Ax concept: set_usage_observer
• Kind: function
• Form: set_usage_observer(observer)
• Returns: void
• Important options: observer, clear

set_usage_observer(Some(Arc::new(move |event| events.lock().unwrap().push(event))));

AxBalancer

Retry and route requests across multiple provider services, with opt-in adaptive cost, reliability, and deadline routing.

• Canonical Ax concept: AxBalancer
• Kind: type
• Form: AxBalancer
• Returns: AI service
• Important options: services, retry policy, capability requirements, adaptive strategy

AxBalancerAdaptiveStrategy

Configure adaptive provider routing without changing the ordered default.

• Canonical Ax concept: AxBalancerAdaptiveStrategy
• Kind: type
• Form: AxBalancerAdaptiveStrategy
• Returns: adaptive strategy
• Important options: deadline, bad outcome cost, expected tokens, stable route keys, slice, stats store, routing events

AxBalancerStatsStore

Store shared adaptive decision state with atomic observations.

• Canonical Ax concept: AxBalancerStatsStore
• Kind: interface
• Form: AxBalancerStatsStore
• Returns: stats store
• Important options: get, observe

AxInMemoryBalancerStatsStore

Thread-safe in-memory adaptive stats store.

• Canonical Ax concept: AxInMemoryBalancerStatsStore
• Kind: type
• Form: AxInMemoryBalancerStatsStore
• Returns: stats store

create_balancer_route_stats

Create neutral adaptive route statistics.

• Canonical Ax concept: create_balancer_route_stats
• Kind: function
• Form: create_balancer_route_stats
• Returns: route stats

update_balancer_route_stats

Purely reduce one success or failure observation into route statistics.

• Canonical Ax concept: update_balancer_route_stats
• Kind: function
• Form: update_balancer_route_stats
• Returns: route stats
• Important options: current stats, observation

sample_balancer_route_health

Sample failure and deadline-miss probability for adaptive exploration.

• Canonical Ax concept: sample_balancer_route_health
• Kind: function
• Form: sample_balancer_route_health
• Returns: sampled health
• Important options: route stats, deadline

MultiServiceRouter

Choose a service by capability or model routing policy.

• Canonical Ax concept: MultiServiceRouter
• Kind: type
• Form: MultiServiceRouter
• Returns: AI service
• Important options: services, routing

ProviderRouter

Route provider requests to registered provider clients.

• Canonical Ax concept: ProviderRouter
• Kind: type
• Form: ProviderRouter
• Returns: AI service
• Important options: providers, routing, processing

Agents And RLM

Run AxAgent through the RLM executor loop with stage instructions, validated evidence citations, persistent playbooks, and actor-code execution through an AxCodeRuntime session.

agent

Create an AxAgent from a signature and agent/runtime options.

• Canonical Ax concept: agent
• Kind: function
• Form: agent(spec: &str)
• Returns: AxResult<AxAgent>
• Important options: name, description, runtime, maxSteps, context fields, discovery, recall, functions, skills, skillsCatalog, memoriesCatalog, relevanceRanking, load observers, used observers, citations, playbook, instruction, instructionAddenda

let helper = agent("query:string -> answer:string")?;

AxAgent

RLM agent with Core-owned envelopes, complete runtime-state export/restore, traces, discovery, recall, loaded skills and memories, usage observers, delegation, validated citations, stage instructions, persistent run-end learning, and verified playbook evolution.

• Canonical Ax concept: AxAgent
• Kind: type
• Form: AxAgent
• Returns: agent program
• Important options: executor model, runtime, policy, context, skills, memories, relevance ranking, observers, runtime state, optimizer metadata, citations, playbook

Flow

Compose AxGen, AxAgent, and nested flows into a portable program graph.

flow

Create an AxFlow program graph or compile the portable Mermaid shorthand.

• Canonical Ax concept: flow
• Kind: function
• Form: flow(source) / flow_with_bindings(source, bindings)
• Returns: AxFlow
• Important options: nodes, execute mappers, conditions, cache, returns, Mermaid roundtrip

let wf = flow("workflow");

AxFlow

Workflow graph with Core-owned planning, cache keys, state merge, child aggregation, optimization, and returns projection.

• Canonical Ax concept: AxFlow
• Kind: type
• Form: AxFlow
• Returns: flow program
• Important options: steps, state, parallel groups, returns

Tools

Expose host functions to AxGen and AxAgent with typed argument and return schemas.

tool

Build a typed function tool. Rust uses tool because fn is reserved.

• Canonical Ax concept: fn
• Kind: function
• Form: tool(name).description(...).arg(...).handler(...).build()
• Returns: ToolBuilder
• Important options: name, description, args, returns, handler

let search = tool("search").description("Search docs").build();

Tool

Callable tool descriptor with JSON-schema-compatible parameters and a host handler.

• Canonical Ax concept: Tool
• Kind: type
• Form: Tool
• Returns: tool descriptor
• Important options: parameters, returns, handler

MCP

Use MCP clients and transports while keeping JSON-RPC lifecycle, tools, prompts, resources, OAuth, cancellation, and SSRF checks aligned.

AxMCPClient

MCP client that lists tools/prompts/resources and converts MCP tools to Ax functions.

• Canonical Ax concept: AxMCPClient
• Kind: type
• Form: AxMCPClient::new(transport, options)
• Returns: MCP client
• Important options: transport, client info, roots, tool overrides

let client = AxMCPClient::new(transport, json!({}));

AxMCPStreamableHTTPTransport

Streamable HTTP transport with session headers, OAuth options, and SSRF protection.

• Canonical Ax concept: AxMCPStreamableHTTPTransport
• Kind: type
• Form: AxMCPStreamableHTTPTransport
• Returns: MCP transport
• Important options: endpoint, headers, OAuth, SSRF protection

AxMCPStdioTransport

Stdio transport with JSON-RPC framing for local MCP servers.

• Canonical Ax concept: AxMCPStdioTransport
• Kind: type
• Form: AxMCPStdioTransport
• Returns: MCP transport
• Important options: command, args, env

Runtime Profiles

Run RLM actor code through the portable AxCodeRuntime and optional target-specific runtime profiles.

ProcessCodeRuntime

Process/JSONL runtime adapter for actor-code sessions and runtime protocol tests.

• Canonical Ax concept: ProcessCodeRuntime
• Kind: type
• Form: ProcessCodeRuntime::new(command)
• Returns: AxCodeRuntime
• Important options: command, env, cwd, timeout

let runtime = ProcessCodeRuntime::new(vec!["node".into(), "runtime-server.mjs".into()]);

RuntimeCapabilities

Runtime capability envelope visible to the agent runtime policy.

• Canonical Ax concept: RuntimeCapabilities
• Kind: type
• Form: RuntimeCapabilities
• Returns: capability record
• Important options: language, snapshot, patch, abort, usage instructions

RuntimeEnvelope

Actor primitive envelope for final, clarification, discovery, recall, used, guidance, and runtime results.

• Canonical Ax concept: RuntimeEnvelope
• Kind: type
• Form: RuntimeEnvelope
• Returns: runtime envelope
• Important options: type, args, result, error

javascript-quickjs

Optional runtime profile for javascript actor code.

• Canonical Ax concept: runtime-profile:javascript-quickjs
• Kind: runtime-profile
• Form: tools/axir verify --targets rust --runtime-profiles javascript-quickjs
• Returns: AxCodeRuntime-compatible actor execution profile
• Important options: actor language: javascript, support mode: embedded, dependency mode: optional-feature, feature gate: runtime-quickjs

Optimizers

Optimize Ax programs through BootstrapFewShot -> GEPA composition and evolve program or agent playbooks through grounded, budgeted, rollback-safe learning.

optimize

Convenience optimizer helper that composes AxBootstrapFewShot before AxGEPA and returns an artifact without applying final component changes.

• Canonical Ax concept: optimize
• Kind: function
• Form: optimize(program, examples, options)
• Returns: AxResult<OptimizedArtifact>
• Important options: student/client, teacher/reflection client, metric budget, bootstrap

let artifact = optimize(&mut qa, train, json!({"maxMetricCalls": 100}))?;

playbook

Bind an ACE-backed playbook to a program; agents also expose an agent-bound playbook handle.

• Canonical Ax concept: playbook
• Kind: function
• Form: playbook(program, student, teacher, options)
• Returns: AxPlaybook
• Important options: student/client, teacher, seed snapshot, online updates, verification budget

let pb = playbook(program, student, None::<Rc<RefCell<OpenAICompatibleClient>>>, json!({}));

AxPlaybook

Persistent playbook with render/update/snapshot operations and agent-bound verified evolve over train/validation task sets.

• Canonical Ax concept: AxPlaybook
• Kind: type
• Form: AxPlaybook / agent.playbook(...)
• Returns: playbook handle
• Important options: verify, minHeldInGain, epsilon, runsPerTask, maxMetricCalls, maxProposals

AxBootstrapFewShot

Few-shot demonstration optimizer that selects successful evaluator rollouts before prompt/component evolution.

• Canonical Ax concept: AxBootstrapFewShot
• Kind: type
• Form: AxBootstrapFewShot::new(options)
• Returns: optimizer engine
• Important options: quality threshold, max demos, max rounds, batch size

let bootstrap = AxBootstrapFewShot::new(json!({"qualityThreshold": 0.7}));

AxGEPA

Generated GEPA optimizer engine with Core-owned reflection, Pareto, bootstrap, and selector-state behavior.

• Canonical Ax concept: AxGEPA
• Kind: type
• Form: AxGEPA::new(reflection, options)
• Returns: optimizer engine
• Important options: reflection client, budget, metric, candidate count

let engine = AxGEPA::new(reflection_client, json!({}));

OptimizerEngine

Optimizer boundary consumed by AxGen, AxAgent, and AxFlow optimization helpers.

• Canonical Ax concept: OptimizerEngine
• Kind: interface
• Form: OptimizerEngine::optimize(request, evaluator)
• Returns: optimized artifact
• Important options: request, evaluator

OptimizerEvaluator

Evaluator callback boundary used by generated optimizers.

• Canonical Ax concept: OptimizerEvaluator
• Kind: interface
• Form: OptimizerEvaluator::evaluate(request)
• Returns: score/evidence result
• Important options: dataset rows, candidate map, evidence

Errors And Values

Handle target-native errors and dynamic values at Ax host boundaries.

AxError

Target-native error envelope for validation, provider, runtime, MCP, and optimizer failures.

• Canonical Ax concept: AxError
• Kind: type
• Form: AxError with target-native error handling
• Returns: error
• Important options: category, message, status, code, retryable

serde_json::Value

Dynamic JSON-like value boundary used by generated package APIs, tools, providers, MCP, and runtime sessions.

• Canonical Ax concept: Value
• Kind: type
• Form: serde_json::Value
• Returns: dynamic value
• Important options: string, number, boolean, object, array, null