pi-params

A pi.dev extension that lets you set per-provider, per-model parameter overrides (temperature, top_p, top_k, frequency_penalty, etc.) by hooking into Pi's before_provider_request event.

How it works

1. You define parameter overrides in .pi/params.toml
2. pi-params tracks the current provider and model via the model_select event
3. Before each provider API request, it injects your overrides into the request payload
4. Overrides work with any provider — OpenAI, Anthropic, Google, OpenRouter, DeepSeek, etc.

Quick start

1. Copy the example config:

   cp .pi/params.example.toml .pi/params.toml

2. Edit .pi/params.toml to your preferences

3. Load the extension:

   pi -e extensions/params.ts

4. Or add to your project's .pi/settings.json for automatic loading:

   {
     "extensions": ["extensions/params.ts"]
   }

Config format

# Global defaults — applies to ALL providers and models
["*"."*"]
temperature = 0.7
top_p = 0.9
max_tokens = 4096

# Provider-level defaults — applies to all models from this provider
["openai"."*"]
frequency_penalty = 0.0
presence_penalty = 0.0

# Per-model — applies only to this specific model on this provider
["openai"."gpt-4o"]
temperature = 0.5
max_tokens = 8192

# Cross-provider model wildcard — applies to this model on ANY provider
["*"."claude-sonnet-4-20250514"]
temperature = 0.25

Merge behavior

Config entries are merged from least specific to most specific. Higher-specificity values override lower-specificity ones:

global (*/*)
  ↓
model wildcard (*/model)
  ↓
provider wildcard (provider/*)
  ↓
exact match (provider/model)

So if you set temperature = 0.7 in */* and temperature = 0.3 in anthropic/*, all Anthropic models get temperature = 0.3.

Slash commands

Use /params commands at runtime to adjust parameters without editing the config file. These session overrides take highest priority and are applied on top of your TOML config.

| Command | Description | |---------|-------------| | /params | Show current provider/model and all active overrides | | /params set <key> <value> | Set a parameter override for this session | | /params unset <key> | Remove a specific session override | | /params preset <name> | Apply a named preset | | /params reset | Clear all session overrides |

Presets

| Preset | temperature | top_p | Other | |--------|-------------|-------|-------| | creative | 1.0 | 0.95 | — | | precise | 0.1 | 0.1 | — | | balanced | 0.5 | 0.8 | — | | code | 0.2 | 0.5 | — | | brainstorm | 1.2 | 0.95 | frequency_penalty 0.5 | | long | — | — | max_tokens 16384 |

Priority chain (highest wins)

TOML global defaults (*/*)
  ↓
TOML model wildcard (*/model)
  ↓
TOML provider wildcard (provider/*)
  ↓
TOML exact match (provider/model)
  ↓
Session overrides (/params commands)  ← highest priority

Supported parameters

| Parameter | Type | Description | |-----------|------|-------------| | temperature | float (0.0–2.0) | Controls randomness. Lower = more deterministic. | | top_p | float (0.0–1.0) | Nucleus sampling threshold. | | top_k | integer | Top-k sampling (common with Anthropic, Google). | | frequency_penalty | float (0.0–2.0) | Penalizes repeated tokens by frequency. | | presence_penalty | float (0.0–2.0) | Penalizes tokens that have appeared. | | repetition_penalty | float (0.0–2.0) | General repetition penalty. | | max_tokens | integer | Maximum tokens in the response. | | stop | string or string[] | Stop sequences. |

Files

| File | Purpose | |------|---------| | extensions/params.ts | The extension itself | | .pi/params.toml | Your active config (create from example) | | .pi/params.example.toml | Example config with all providers and params |

Requirements

• pi.dev CLI
• npm dependency: smol-toml (installed via npm install in this project)

License

MIT