Transport Configuration

Transport config lives at ~/.abtars/config/transport.json. It defines which AI providers are available and which models each agent uses.

Terminology

Term	Definition
Provider	A named service entry — identifies how to reach a model
Route	Normal execution route: pi-ai for API providers or acp for CLI providers
Transport	Provider communication method: acp (CLI via JSON-RPC) or api (HTTP endpoint)

Example

{
  "schemaVersion": 3,
  "activeRoute": "pi-ai",
  "routes": {
    "pi-ai": {
      "agents": {
        "main": { "model": "deepseek/deepseek-v4-flash", "provider": "openrouter" },
        "dreamy": { "model": "deepseek/deepseek-v4-flash", "provider": "openrouter" },
        "browsie": { "model": "deepseek/deepseek-v4-flash", "provider": "openrouter" },
        "cody": { "model": "deepseek/deepseek-v4-flash", "provider": "openrouter" }
      },
      "fallbacks": [
        { "model": "google/gemini-2.5-flash", "provider": "openrouter" }
      ]
    },
    "acp": {
      "agents": {
        "main": { "model": "claude-sonnet-4.6", "provider": "kiro" }
      },
      "fallbacks": []
    }
  },
  "providers": {
    "kiro": { "transport": "acp", "cli": "kiro-cli" },
    "gemini": { "transport": "acp", "cli": "gemini" },
    "ollama": { "transport": "api", "endpoint": "http://localhost:11434/v1" },
    "openrouter": { "transport": "api", "endpoint": "https://openrouter.ai/api/v1", "apiKeyEnv": "OPENROUTER_API_KEY" }
  },
  "maxTurns": 50,
  "hailMary": {
    "route": "acp",
    "model": "claude-sonnet-4.6",
    "provider": "kiro"
  },
  "healthPolicy": {
    "skipThreshold": 0.7,
    "leakPerMinute": 0.03,
    "rateLimitFill": 0.5,
    "transientProgressive": [0.1, 0.2, 0.4, 0.8],
    "transientCooldownAfter": 3,
    "transientMaxCooldownSec": 300
  }
}

Route-local assignments

Agent	Role
main	Main conversation agent
dreamy	Sleep cycle / dream processing
browsie	Web browsing tasks
cody	Coding mode

Each route has its own agents and fallbacks assignments. Switching with /route pi-ai or /route acp changes only activeRoute; the other route's selections are preserved.

Fallback Chain

Each active route supports an ordered fallbacks array. When the primary model fails:

1. Try fallback 1, 2, 3, ... N (in order)
2. Skip models with full health buckets (rate-limited, auth failed)
3. If all exhausted → error. The global ACP-only hailMary descriptor powers the manual /emergency fast path (a dedicated ACP client outside the normal pipeline).

Fallbacks must use providers compatible with their route. ACP assignments use one ACP provider; pi-ai assignments use API providers.

Add fallbacks to the selected route's array in transport.json.

Health Policy

The bridge tracks model health using a leaky-bucket algorithm. Errors fill the bucket, time drains it. Full bucket = model skipped.

All values in healthPolicy are optional (defaults shown above):

Field	Default	Description
skipThreshold	0.7	Bucket level (0-1) above which model is skipped
leakPerMinute	0.03	How fast a penalized model recovers
rateLimitFill	0.5	Penalty per rate-limit hit (429)
weakFill	0.05	Mild penalty for weak responses
transientProgressive	[0.1, 0.2, 0.4, 0.8]	Escalating penalty per consecutive error
transientCooldownAfter	3	Errors before hard cooldown
transientMaxCooldownSec	300	Maximum cooldown duration

Adding a Provider

Add an entry to providers and restart:

"my-provider": {
  "transport": "api",
  "endpoint": "https://api.example.com/v1",
  "apiKeyEnv": "MY_PROVIDER_KEY"
}

Then assign an agent to it or use /model change to switch interactively.

Model Switching

Action	What happens
/model restore	Undo last switch (swaps transport.json with .old backup)
/model default	Factory reset from transport.default.json
Model change, same transport	New session (conversation reset)
Provider change (different transport)	Full reset (transport rebuilt)