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