Habakkuk makes many small yes/no decisions around your conversations. By default it makes them with word rules or a full model call. A decision model answers typed questions with a probability in well under a second, for a fraction of a cent, so these decisions get both cheaper and better.

Habakkuk supports TypeSafe's Jev. It never writes replies; your agents' models still do that.

yaml

judge:
  model: jev-latest              # default
  timeout_ms: 800                # past this, Habakkuk decides without it
  routing: true                  # which model a message needs (default true)
  approvals: true                # screen tool calls before the reviewer model (default true)
  memory: true                   # skip memory reviews of chats with nothing to keep (default true)

Put the key in $HABAKKUK_HOME/.env as TYPESAFE_API_KEY (or name another variable with key_env). Without a key, or when the API is slow or down, everything works as it does without a judge: section.

What it decides#

Decision	Without a decision model	With one
Routing. For agents with a `fast_model`: quick message or real work?	Word rules (build, fix, research, long text, code...)	One question about the message and whether the last turn was real work. Attachments still always go to the main model. See Routing.
Approvals. For agents with `approvals: reviewer` or `reviewer_then_human`: is this tool call plainly routine?	A model call reviews every call	A call it is at least `approve_above` (0.97) sure is routine, and at most 3% likely to be risky, is allowed without the model call. Anything else goes to the reviewer model as before.
Memory. Is this chat worth a memory review?	A model call reviews every quiet session	A chat it rates under `skip_memory_below` (0.15) is skipped; the rest are reviewed as before.

Important

The decision model can only make approvals faster, never looser. It never denies or asks on its own, never decides for a turn that has read outside content (a web page, an email), and the commands Habakkuk always blocks stay blocked. Raise approve_above towards 1 to use it less, or set approvals: false to keep every review on the reviewer model.

Cost#

Input costs $0.042 per million tokens and output is free. A routing decision is about 100 to 200 tokens, so a million decisions cost a few dollars. Calls are recorded in usage.db under the provider typesafe, show up in habakkuk usage, and count toward spending limits.

Settings#

Key	Default
`model`	`jev-latest`	A model id, for example `jev-1.14.0` to pin a version
`base_url`	`https://api.typesafe.ai/v1`	The API, or a gateway that serves the same API
`key_env`	`TYPESAFE_API_KEY`	The variable in `.env` that holds the key
`timeout_ms`	800	How long a decision may take (100 to 10000)
`routing`, `approvals`, `memory`	`true`	Which decisions it makes
`approve_above`	0.97	How sure it must be that a tool call is routine (0.9 to below 1)
`skip_memory_below`	0.15	Below this, a chat's memory review is skipped (0 to 0.5)