agentyper 0.1.9

Agent-first Python CLI library — Typer-compatible, built on argparse + pydantic

agentyper

Agent-first Python CLI library — built on argparse + pydantic, Typer-compatible.

Typer was built for the era when type hints changed Python.
agentyper is built for the era when AI agents changed how software is operated.

Why Agentyper?

Typer was built for humans. Agents need something different.

Typer revolutionized CLI development by elegantly using type hints. However, because it is built on Click and Rich, it is fundamentally optimized for human eyeballs. When interacting with standard CLIs, AI Agents struggle: they cannot organically discover the tool's schema, they get blocked by interactive prompts ([y/N]), they hallucinate when parsing ANSI-colored tables, and they fail to self-correct when errors are returned as flat strings.

Agentyper keeps the beloved Developer Experience (DX) of Typer but replaces the execution engine with argparse and Pydantic. With a one-line switch (import agentyper as typer), your CLI instantly yields OpenAPI/JSON schemas, strict Pydantic structured errors, and deterministic programmatic overrides for interactive features.

📖 Learn more in our docs:

• For Agents: How to use an agentyper CLI — schema discovery, format flags, error JSON, bypass flags
• For Developers: Building agent-friendly CLIs — best practices, output patterns, testing
• Agent Requirements for CLI Tools
• Why Agentyper? (Alternatives & Comparison Matrix)

agentyper implements the CLI Agent Spec — a formal specification for agent-ergonomic CLI tools.

Install

pip install agentyper

Quick Start

Absolute minimum:

Create a main.py:

def main(name: str):
    print(f"Hello {name}")

Run it without importing anything:

agentyper main.py run Camila

Single function (like typer.run()):

import agentyper

def search(ticker: str, limit: int = 10):
    """Search securities by ticker."""
    results = service.search(ticker, limit)
    agentyper.output(results)   # routes via --format automatically

agentyper.run(search)

Multi-command app:

import agentyper

app = agentyper.Agentyper(name="my-tool", version="1.0.0")

@app.command()
def search(ticker: str, limit: int = agentyper.Option(10, help="Max results")):
    """Search securities."""
    agentyper.output(service.search(ticker, limit))

@app.command()
def delete(name: str):
    """Delete a record."""
    if agentyper.confirm(f"Delete '{name}'?"):
        service.delete(name)

app()

Typer migration — one line:

# import typer          ← before
import agentyper as typer  # ← after; everything else stays identical

What Agents Get for Free

Every command automatically gains:

my-tool --schema                  # full JSON Schema of the entire app
my-tool search --schema           # JSON Schema for this command's params
my-tool search AAPL --format csv  # 4× cheaper output than table
my-tool search AAPL --format json # structured JSON output
my-tool delete alice --yes        # skip confirm() in agent mode
my-tool wizard --answers '{"confirms":[true],"prompts":["Alice","admin"]}'

If you are an agent consuming an agentyper CLI, read docs/for-agents.md for schema discovery, error handling, and the full flag reference.
If you are building a CLI with agentyper, read docs/for-developers.md for patterns, best practices, and a pre-ship checklist.

Agent Ergonomics

Feature	agentyper	Typer
--schema on every command	✅ automatic	❌ manual
--format json/csv/table	✅ automatic	❌ manual
Structured JSON errors	✅ automatic	❌ free text
Exit code taxonomy (0/1/2)	✅	❌ 0 or 1
Interactive features in agent mode	✅ --yes/--answers bypass	❌ blocks
isatty() auto-format detection	✅	❌
Dependencies	argparse + pydantic	Click + Typer

Typer Compatibility Matrix

agentyper implements Typer's core API. For most CLIs, import agentyper as typer works flawlessly. Because it is built from scratch on argparse + Pydantic (for LLM reliability) instead of Click, there are some differences.

Feature / API	Status	Notes
@app.command(), @app.callback()	✅ Supported	Core app routing works identically.
Option(), Argument()	✅ Supported	Core args mapping (default, help, etc.)
Type Hint Extraction	✅ Supported	Uses Pydantic for robust validation.
Interactive Prompts (confirm())	✅ Supported	Enhanced with non-blocking agent overrides.
typer.Context (ctx)	✅ Supported	Invocation-scoped context exposes ctx.format, ctx.runtime, ctx.root, ctx.params, and ctx.obj. click-specific methods (ctx.forward(), ctx.meta) still do not exist.
click Parameter Types	❌ Unsupported	Fully replaced by Pydantic. Use Literal["A"] instead of click.Choice.
typer.style(), colors	❌ Unsupported	Removed. Agents prefer plain text or structured JSON.
Custom Click logic	❌ Unsupported	Executed purely via standard argparse.

Exit Codes

agentyper.EXIT_SUCCESS    = 0  # success
agentyper.EXIT_VALIDATION = 1  # bad input — agent should retry with correction
agentyper.EXIT_SYSTEM     = 2  # system error — agent should abort

Interactive Features

All interactive features from Typer work identically in a terminal. In agent/non-TTY mode, they resolve without blocking:

# Human terminal: asks interactively
my-tool delete alice

# Agent: auto-confirm via flag
my-tool delete alice --yes

# Agent: pre-supply all answers
my-tool wizard --answers '{"confirms":[true,false],"prompts":["Alice","admin"]}'

# Agent: pipe answers from stdin
echo '{"confirms":[true]}' | my-tool delete alice --answers -

Invocation Context

Commands and callbacks can accept ctx: agentyper.Context to inspect the resolved invocation state:

@app.command()
def sync(ctx: agentyper.Context, target: str):
    client = build_client(ctx)
    agentyper.output({"target": target, "format": ctx.format})

Helper code can also read the active invocation context without manually threading it through every call:

def build_client(ctx: agentyper.Context | None = None) -> Client:
    ctx = ctx or agentyper.get_current_context()
    return Client(timeout_ms=ctx.runtime.timeout_ms, verbose=ctx.runtime.verbosity > 0)

License

MIT