Auto mode, /btw command, and model size display #21

Why

Problem 1: Permission friction blocks autonomous work

The current --dangerously-skip-permissions flag is a blunt instrument — it disables ALL permission checks, including safety-critical ones. Claude Code's auto mode provides a better pattern: a classifier-based approach that auto-approves safe actions (file reads, local writes) while routing risky actions (shell commands, network calls, production deploys) through a safety classifier. Users want full autonomy without the security risk of bypassing all checks.

Problem 2: No way to ask side questions during agent work

Claude Code's /btw command lets users ask quick questions without cluttering conversation history. When the agent is mid-task (especially in a loop), users need to ask "what was that config file name?" or "what did we decide about X?" without derailing the main work or adding noise to the context window.

Problem 3: Model size (GB) not visible outside the repo

Local llama-skein models report size_bytes in their /v1/models endpoint, and the Model.sizeBytes field exists in the schema (provider.ts:1114), but it's never populated or displayed outside the repo where the llama-skein backend is directly accessible. The discoverOpenAICompatibleModels function at provider.ts:1536 reads size_bytes from the API response, but the fit report (/api/fit) also contains model_mb which could be used as a fallback. Additionally, the mergeDiscoveredModel function at provider.ts:1460 preserves sizeBytes correctly, but the initial discovery may not be getting the data.

What Changes

Auto mode

• Replace --dangerously-skip-permissions with --auto flag (and --permission-mode auto)
• Create an AutoMode service that evaluates tool calls against safety rules
• Safe actions (file reads, local edits in working directory) auto-approve
• Risky actions (shell commands, network calls, destructive operations) route through a classifier-like evaluation
• Add permission mode cycling (Shift+Tab equivalent) in TUI
• Support defaultMode: "auto" in settings
• Classifier rules: block downloads+execution, sensitive data exfiltration, production deploys, mass deletions, IAM changes, force push, etc.
• Allow explicit ask rules to still force prompts even in auto mode

/btw command

• Create a /btw slash command for temporary side questions
• Side questions have full visibility into current conversation context
• No tool access — answers only from existing context
• Single response in a dismissible overlay
• Does not add to conversation history
• Can run while agent is processing (independent of main turn)
• Reuses parent conversation's prompt cache for low cost

Model size display fix

• Ensure size_bytes from /v1/models is properly captured during discovery
• Add fallback: use model_mb from /api/fit report when size_bytes is unavailable
• Display size in GB format in model picker and opencode models output
• Fix the data flow: /v1/models → discoverOpenAICompatibleModels → sizeBytes field → model picker UI

Capabilities

New Capabilities

• auto-mode: classifier-based permission mode that auto-approves safe actions while routing risky ones through safety evaluation
• side-questions: temporary /btw command for asking questions without adding to conversation history

Modified Capabilities

• permissions: enhanced with mode system (default, acceptEdits, auto, dontAsk, bypassPermissions)
• model-picker: now displays model size in GB for local models

Non-Goals

• Not implementing a full ML-based classifier (that's a server-side concern)
• Not changing the loop engine's core behavior
• Not adding persistent storage for side questions
• Not implementing Claude Code's full permission mode cycle (Shift+Tab) in this change — just the --auto flag and settings support

Impact

• Modified: packages/opencode/src/cli/cmd/run.ts (replace --dangerously-skip-permissions with --auto)
• Modified: packages/opencode/src/permission/index.ts (add mode evaluation)
• Modified: packages/opencode/src/session/tools.ts (route through auto mode)
• New: packages/opencode/src/cli/cmd/btw.ts (/btw command implementation)
• New: packages/opencode/src/auto-mode/ (auto mode service and rules)
• Modified: packages/opencode/src/provider/provider.ts (model size fallback from fit report)
• Modified: packages/opencode/src/cli/cmd/models.ts (display size in output)
• Modified: packages/opencode/src/config/config.ts (add auto mode config)

Disposition (2026-09-18)

Archived — superseded/obsolete. /btw exists as the side-question command; auto mode exists (--auto, auto_mode, footer badge fixed 2026-09-18). The safety-rule categories were never wanted over the permission system.