ax() API

Structured generation APIs for typed programs.

Most Used

`ax`

Create an AxGen program from a string or parsed signature.

Field	Value
Kind	`function`
Ax concept	`ax`
API section	AxGen
Form	`ax(signature, options=None)`
Returns	AxGen

Important Options

functions
examples
demos
sample count
result picker
modelConfig
maxRetries
streaming assertions
field processors
control
asyncMode

Examples

Python

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

Full reference

`AxGen`

Structured generation program with indexed multi-sampling, winner selection, forward, streaming, optimization, trace, usage, and tool-call behavior.

Field	Value
Kind	`type`
Ax concept	`AxGen`
API section	AxGen
Form	`AxGen(signature, options=None)`
Returns	program object

Important Options

signature
functions
examples
demos
sample count
result picker
memory
prompt template

Full reference

`fn`

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

Field	Value
Kind	`function`
Ax concept	`fn`
API section	Tools
Form	`fn(name).description(...).arg(...).handler(...).build()`
Returns	tool builder or Tool

Important Options

name
description
args
returns
handler
execution: blocking or background
cancellation-aware handler

Examples

Python

search = fn("search").description("Search docs").arg("query", f.string()).build()

Full reference

Advanced / internals / full reference

`run_control`

Create a controller for scoped steering, reasoning updates, cancellation, and queued/applied lifecycle events. Pass it through forward options.

Field	Value
Kind	`function`
Ax concept	`run_control`
API section	AxGen
Form	`run_control()`
Returns	AxRunControl

Examples

Python

control = run_control()

Full reference

`AxRunControl`

Run control shared by active and future descendant programs. Cancellation reports unresolved work and does not undo external effects.

Field	Value
Kind	`type`
Ax concept	`AxRunControl`
API section	AxGen
Form	`AxRunControl`
Returns	run controller

Important Options

steer
thinking token budget
target path
abort
event listener

Full reference

`Callable[[str, dict | None], dict | None]`

TypeScript’s cachingFunction: read and store finished AxGen outputs by key. The forward call’s function comes first, then the program’s, then the process-wide one, and a run control skips the cache.

Field	Value
Kind	`type`
Ax concept	`AxCachingFunction`
API section	AxGen
Form	`caching_function(key, output=None)`
Returns	stored output or miss

Important Options

read
store
SHA-256 key
streamed hit as one delta

Examples

Python

qa = ax("question:string -> answer:string", {"caching_function": cache})

Full reference

`set_caching_function`

Field	Value
Kind	`function`
Ax concept	`set_caching_function`
API section	AxGen
Form	`set_caching_function(fn)`
Returns	void

Important Options

caching function
clear

Examples

Python

set_caching_function(cache)

Full reference

`Tool`

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

Field	Value
Kind	`type`
Ax concept	`Tool`
API section	Tools
Form	`Tool(name, description, parameters, handler)`
Returns	tool descriptor

Important Options

parameters
returns
handler

Full reference

Full Reference

Open the full Python reference. This page highlights the ax symbols most relevant to everyday use.