Switching models mid-conversation

Experimental. /provider use <name> changes which model answers you, without restarting your session. /provider auto puts it back.

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The idea in one line

Each entry in your provider list is one account plus one model, and you give it a short name you can type.

That means "my work account's Opus" and "my personal account's Opus" are two entries, not one. So are "Opus" and "Haiku" on the same account.

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Step 1 — set up your providers

Providers live in ~/.amplifier/settings.yaml under config.providers. Here is a real, working example: two different Anthropic accounts, four models, four names you can type.

config:
  providers:
    # --- main account ---
    - id: opus
      module: provider-anthropic
      config:
        api_key: ${ANTHROPIC_API_KEY}
        default_model: claude-opus-5
        priority: 1              # lowest number wins -> this is your default

    - id: sonnet
      module: provider-anthropic
      config:
        api_key: ${ANTHROPIC_API_KEY}
        default_model: claude-sonnet-5
        priority: 2

    - id: haiku
      module: provider-anthropic
      config:
        api_key: ${ANTHROPIC_API_KEY}
        default_model: claude-haiku-4-5
        priority: 3

    # --- second account, different key ---
    - id: fable
      module: provider-anthropic
      config:
        api_key: ${ANTHROPIC_FABLE_API_KEY}   # <- the only thing that differs
        default_model: claude-fable-5
        priority: 4

Two things are doing all the work:

Field	What it does
id	The name you type: /provider use fable
priority	Lowest number is your default. Here that's opus.

Everything else — the key, the model, the module — is just configuration for that one entry.

Check it worked:

amplifier provider list     # should show all four, ★ on your default
amplifier provider test     # confirms each key actually works

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Step 2 — use it

Inside an interactive session:

> /provider
   ...shows what's available; ★ marks what your priority order favors

> /provider use fable
📌 pinned: fable
   experimental · scope: this conversation only · /provider for details

[📌 fable]> what do you think of this design?
   ...answered by claude-fable-5

[📌 fable]> /provider auto
unpinned (was fable)

>              ← back to your default (opus)

While pinned, your prompt shows [📌 fable] and every reply's usage line ends with · 📌 pinned. You never have to guess which model you're talking to.

Note the usage line names the model (claude-fable-5), while the prompt names your id (fable). If you ever give two entries the same model, the prompt is the one that tells them apart.

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Naming your providers

The id is yours to choose. Pick names you'd actually want to type.

id: opus              # short — good when you have one account
id: fable             # short — the model IS the reason this entry exists

id: opus-work         # when the same model exists on two accounts
id: opus-home

id: anthropic-home    # when the account matters more than the model

A few things that help:

• Short beats descriptive. You'll type this a lot.
• Name what actually differs. If you have one account, name by model (opus, haiku). If you have several, add the account (opus-work).
• id must be unique. Two entries with the same id will collide.
• id is optional — without it the name defaults to the module (anthropic), which is fine for exactly one entry and confusing for more. If you have more than one entry per provider, set id on all of them.

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Setting your default

Your default is simply the entry with the lowest priority number.

To make Opus your default and keep Fable on hand, give Opus priority: 1 and Fable a higher number. /provider auto always returns you to whatever this says.

Nothing about pinning changes your default — a pin lasts for the session and disappears when you exit. To change your default permanently, edit settings.yaml (or use amplifier provider edit).

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Limits worth knowing

Same vendor only. You can switch freely among Anthropic entries, or among OpenAI entries — but not from Anthropic to OpenAI mid-conversation. Your conversation history contains vendor-specific data that other vendors reject, and switching across vendors can leave a session unable to continue. Amplifier refuses the switch up front and tells you why.

To use a different vendor, start a new session with amplifier run -p <name>.

Session only. A pin lasts until you exit. It does not persist and does not change your saved settings.

Top-level only. Pinning affects the conversation you're having. Sub-agents, model-role routing, and /goal are unaffected — they keep using whatever your configuration says.

Depends on your orchestrator. Pinning is a capability the orchestrator provides, and not every orchestrator does. If yours doesn't, /provider tells you plainly instead of pretending the switch worked. The default orchestrator (loop-streaming) supports it.

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Two provider commands, two jobs

They look similar and do different things:

	Where	What it does
amplifier provider ...	Your shell	Manages saved configuration — add, edit, list, test, remove
/provider ...	Inside a session	Pins the current conversation — use, auto. Changes nothing on disk.
amplifier run -p <name>	Your shell	Starts one session on a specific provider

Rule of thumb: amplifier provider changes what's available tomorrow. /provider changes who's answering right now.

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Quick reference

/provider                 show providers and what's active
/provider use <name>      pin this conversation to <name>
/provider auto            unpin — back to your default

amplifier provider list   show configured providers
amplifier provider test   check every key works
amplifier run -p <name>   start a session on <name>