prompt-template-authoring

name	prompt-template-authoring
description	Write and run custom Pi prompt templates (slash commands) for this extension. Use when creating templates with model selection, deterministic pre-steps, loops, chains, subagents, or best-of-N compare flows.

Prompt Template Authoring

Use this skill when working on prompt templates for pi-prompt-template-model. Templates are markdown files that register as slash commands.

Where Templates Live

• ~/.pi/agent/prompts/ — user prompts (highest priority)
• .pi/prompts/ inside a trusted project — project-specific prompts

Extension examples/ are reference files only. Copy them to a prompt directory to register them.

Minimal Template

---
model: claude-sonnet-4-20250514
---
Your prompt body here.

Save as my-command.md, restart Pi, run /my-command. Use description: for autocomplete text.

Model Selection

Omit model: to inherit the current session model. Otherwise:

• model: claude-sonnet-4-20250514 — specific model
• model: claude-opus-4, gpt-5.4 — fallback order (tries first, falls back to second if unavailable)
• model: claude-opus-4, gpt-5.4 + rotate: true — cycle through list on each loop iteration

Argument Substitution

The prompt body can use placeholders:

• $@ — all arguments passed to the command
• $1, $2 — specific positional arguments
• ${@:1} — argument 1 and everything after

Deterministic Steps (Pre-LLM Execution)

Run a command or script before the LLM turn. The model only sees the output if you want it to.

Two equivalent forms. Don't mix them in the same prompt.

Shorthand form — top-level keys:

---
run: git status --short
handoff: always
---
Summarize the repo state.

Nested form — under deterministic::

---
deterministic:
  run: ./scripts/ship.sh
  handoff: on-failure
  timeout: 60000
---
Diagnose the failure and suggest a fix.

Handoff controls when the LLM sees the result:

• never — run, show result, done (no LLM turn)
• always — always hand result to model
• on-failure — only hand off if command exits non-zero
• on-success — only hand off if command exits zero

Execution forms:

• run: command string — runs via /bin/bash -lc
• run: {command: git, args: [status], shell: false} — explicit args, optional shell
• script: ./script.sh or script: {path: ./script.sh, args: [--fast]} — run a file

Constraints:

• Only single prompt templates (no chain, loop, subagent, or parallel)
• Runtime flags --loop, --subagent, --fork are rejected for deterministic prompts

Subagent Delegation

Delegate to another Pi agent instead of running inline:

---
model: claude-sonnet-4-20250514
subagent: delegate          # or true, or a specific agent name
inheritContext: true        # fork conversation context (optional)
cwd: /absolute/path         # working directory for the subagent (optional)
parallel: 3                 # run 3 copies in parallel (optional)
---
$@

Requires pi-subagents to be installed.

Loops

Run the prompt multiple times:

---
model: claude-sonnet-4-20250514
loop: 5                     # run exactly 5 times
converge: true              # stop early if no changes (default)
fresh: true                 # collapse context between iterations
---
$@

Or at runtime: /command --loop 5, /command --loop (unlimited), or /command --loop=5 --fresh.

Chains

Chain templates declare a reusable pipeline:

---
chain: analyze -> fix -> test
chainContext: summary        # pass step summaries to later delegated steps
---
$@

Or use /chain-prompts analyze -> fix -> test at runtime. Chain templates ignore the body and model: field.

Model Conditionals

Show different content based on which model runs:

<if-model is="anthropic/*">
Use Claude-specific instructions.
<else>
Use default instructions.
</if-model>

Supports exact IDs, provider/model-id pairs, wildcards (anthropic/*), and comma-separated combinations.

Best-of-N Compare

Run multiple workers, aggregate with reviewers, optionally apply final changes:

---
description: Best-of-N code review
bestOfN:
  worktree: true            # required if using finalApplier
  workers:
    - model: openai-codex/gpt-5.4-mini:low
      count: 2
  reviewers:
    - model: anthropic/claude-sonnet-4-20250514:medium
  finalApplier:
    agent: delegate
    model: anthropic/claude-sonnet-4-20250514:high
---
$@

Runtime Flags

Override frontmatter at invocation:

• --model=provider/model-id — use this model instead
• --subagent / --subagent=<name> / --subagent:<name> — force delegation
• --fork — force delegation with context fork
• --loop N / --loop=N / --loop — override loop count (unlimited if bare)
• --fresh — collapse context between iterations
• --no-converge — run all iterations even if no changes
• --cwd=/absolute/path — working directory override when the prompt supports cwd
• --chain-context — pass summaries to later delegated chain steps
• --worktree — use git worktrees for parallel delegated work

When stuck, check README.md and examples/best-of-n.md in this extension.