oy-cli 0.3.2

Tiny local coding CLI with a small tool surface

oy-cli

Tiny AI coding assistant for your shell. Reads files, runs commands, makes precise edits, and stays intentionally small.

uv tool install oy-cli
oy "add docstrings to public functions"

Examples

# Basic usage
oy "read the main module and suggest improvements"

# Work in a specific directory
OY_ROOT=./my-project oy "fix the failing tests"

# Non-interactive mode (CI/pipelines)
echo "update the changelog" | OY_NON_INTERACTIVE=1 oy

# Security audit
oy audit
oy audit "focus on authentication"

Commands

oy "prompt"              # Run with a prompt (default)
oy chat                   # Interactive multi-turn session
oy audit                  # Security audit against OWASP ASVS/MASVS
oy model                  # Show current default model
oy model <filter>         # Pick/save a model
oy --help                 # Show all commands

Why This Exists

Most AI coding tools are large, complex, or lock you into a single provider. oy is deliberately small, easy to audit, and built around a narrow tool surface.

Design goals: small auditable codebase, minimal tool surface, OpenAI-completions-focused CLI loop, multiple backends behind shims, fresh session each run, and explicit checkpoints when needed.

System Prompt

The system prompt is intentionally short. Tool semantics live with the tool definitions; the system prompt focuses on operating rules and judgment:

You are oy, a tiny coding cli with tools. Work by inspecting first, then making explicit changes. Prefer simple auditable solutions. Keep going until done or genuinely blocked; if blocked, say what you tried and next steps. Use grugbrain-style simplicity for complexity, OWASP-minded judgment for security, and performance-aware judgment to avoid obvious waste.

In interactive mode, the ask tool is available: "Use ask only when significant clarification or direction is needed."

In non-interactive mode (OY_NON_INTERACTIVE=1): "Non-interactive mode: do not pause for approval."

Tools

Each tool description is passed directly to the model. These are the exact descriptions:

Tool	Description
list	List a directory. Use this first on unfamiliar trees. Returns sorted entries, one per line, with / for directories.
read	Read a file or directory. Use before editing. Files return line-numbered text; directories fall back to list. Use offset/limit for large files.
apply	Edit files inside the workspace. Operations: replace, write, move, delete. Read first and keep edits precise.
bash	Run shell commands for tests, builds, git, and scripts. Do not use for routine file inspection. Returns stdout and stderr together.
grep	Search file contents by text or regex. Use file_glob to narrow by filename pattern. Returns matching lines with file and line numbers.
glob	Find files by name pattern like *.py or src/**/*.js. Use when you know the path shape. Supports *, ?, and **.
httpx	Fetch web pages or APIs over HTTP(S). Presets: page, json, post_json. Use json_path to extract nested fields. Sensitive headers are redacted.
ask	Ask the user a question in interactive runs. Use for significant ambiguity or decisions. Provide choices when useful.

Output truncation: tool output is clipped to preserve context window; bash keeps both head and tail. When clipped, narrow the next query.

Audit Command

oy audit runs the agent with a dedicated system prompt:

Audit the repo for security, unnecessary complexity, and major obvious performance issues. Fetch current OWASP ASVS and MASVS with httpx, inspect the codebase, and write/merge prioritised findings to ISSUES.md. Each finding should include location, category (security|complexity|performance), reference, recommendation, and status: OPEN. Avoid removing project or human context.

oy audit                    # Full audit
oy audit "focus on auth"    # With focus area
OY_ROOT=./src oy audit      # Audit specific directory

Configuration

Environment variables:

Variable	Purpose
OY_MODEL	Override model for this session (bare name or shim:model)
OY_SHIM	Force a specific shim: openai, codex, gemini, claude, bedrock, or bedrock-mantle
OY_NON_INTERACTIVE	Set to 1 to disable checkpoints
OY_ROOT	Run against different workspace
OY_SYSTEM_FILE	Append extra system instructions
OY_CONFIG	Override config path (default: ~/.config/oy/config.json)

Tuning variables (rarely needed):

Variable	Default	Purpose
OY_MAX_TOOL_OUTPUT_TOKENS	4096	Max tokens kept from tool output
OY_MAX_TOOL_TAIL_TOKENS	1024	Tail tokens preserved when output is clipped
OY_MAX_BASH_CMD_BYTES	65536	Max command size for bash tool
OY_MAX_CONTEXT_TOKENS	131072	Context window budget
OY_MAX_MESSAGE_TOKENS	4096	Per-message truncation limit
OY_DEFAULT_MAX_STEPS	512	Max LLM turns per run
OY_DEFAULT_MAX_TOOL_CALLS	512	Max tool invocations per run
OY_DEFAULT_LINE_LIMIT	500	Default line limit for read/list/glob
OY_BEDROCK_READ_TIMEOUT	120	HTTP read timeout for Bedrock (seconds)
OY_BEDROCK_MAX_OUTPUT_TOKENS	4096	Max output tokens for Bedrock Converse

Config file (~/.config/oy/config.json):

{"shim": "gemini", "model": "gemini-2.5-pro"}

The shim field pins which backend to use regardless of what else is signed in. Use oy model <filter> to pick interactively; it merges models from available signed-in shims into a single list using shim:model prefixes.

On first run, if no model is configured, oy prompts you to pick one from the available backends. Set OY_MODEL, OY_SHIM, or save a config with oy model to pin behavior.

Recommended model: From testing, glm-5 (via Bedrock) offers the best balance of intelligence, cost, and tool-use ability. kimi-k2.5 is another strong option.

Requirements

• Python 3.14+
• bash
• (Optional) rg (ripgrep) for faster search
• OpenAI API key or Codex local auth OR Gemini CLI OAuth credentials (~/.gemini/oauth_creds.json) OR Claude Code local auth OR AWS CLI configured for Bedrock

Installation

uv tool install oy-cli  # Preferred
pip install oy-cli       # Alternative

Authentication

OpenAI:

export OPENAI_API_KEY=sk-...

For OpenAI-compatible endpoints:

export OPENAI_BASE_URL=https://your-endpoint.example/v1
export OPENAI_API_KEY=...

Codex CLI (automatic): If you have already logged in with codex, oy will reuse the credentials in ~/.codex/auth.json. If that file contains a generated API key, oy uses the public OpenAI Responses API. If it contains a ChatGPT account session instead, oy uses the ChatGPT-backed Codex responses endpoint.

Gemini CLI (automatic): If you have the Gemini CLI installed and have run gemini at least once to authenticate, oy will pick up the OAuth credentials automatically from ~/.gemini/oauth_creds.json. No extra setup needed.

# Install and authenticate the Gemini CLI once
npm install -g @google/gemini-cli
gemini  # follow the login prompt

# Then just use oy — it auto-detects Gemini credentials
oy "refactor this function"

Default model when using Gemini: gemini-2.5-pro. Use oy model <filter> or OY_MODEL to switch.

Claude Code (automatic): If you have already signed in with Claude Code, oy can use that local session directly through the claude shim. No Anthropic API key is required.

claude auth login
oy --model claude:sonnet "refactor this function"

AWS Bedrock (automatic): Uses your default AWS profile/region. Supports auto-refresh of stale SSO sessions.

export AWS_PROFILE=my-profile
export AWS_REGION=us-west-2

Troubleshooting

"Missing API credentials" -> Set OPENAI_API_KEY, sign in with codex, install and authenticate the Gemini CLI, sign in with claude auth login, or configure AWS CLI (aws configure). For Bedrock: ensure your profile has bedrock:InvokeModel permission.

"stdin is not a TTY" -> Piping input disables ask. Set OY_NON_INTERACTIVE=1 to make explicit.

"AWS SSO session is stale" -> Run aws sso login --use-device-code --no-browser or run oy in a TTY for auto-prompt.

"command timed out" -> bash default timeout is 120s. Agent can increase timeout_seconds parameter.

"replace target not found" -> apply requires exact string match. Read file first, check whitespace.

Output truncated -> Tools clip at 4096 tokens by default. Agent auto-narrows queries, or guide explicitly: "read lines 100-200".

Security

oy can run shell commands and modify files with your permissions. Treat it like any other local automation tool.

Recommended:

• run in a repo or workspace you trust
• mount only needed directories in containers
• avoid exposing long-lived secrets in the environment
• review generated changes before shipping

Automatic protections: workspace-bound file access, structured edits through apply, sensitive header redaction in httpx, and native boto3 credential resolution for Bedrock.

Links

• Issues - Known issues and audit findings
• Contributing - Development and release notes

License

Apache License 2.0