claude-code-usage-bubble/plans/260602-1115-opencode-go-provider-support/phase-03-implement-opencode-go-provider.md

phase, title, status, priority, effort, dependencies

phase	title	status	priority	effort	dependencies
3	Implement OpenCode Go provider	pending	P1	5h	1 2

Phase 3: Implement OpenCode Go Provider

Overview

Add OpenCode Go credential discovery and polling once Phase 1 proves the source of truth.

Requirements

• Functional: When enabled and authenticated, OpenCode Go returns weekly/monthly usage percent and reset time, enough for four bars: usage percent + remaining time for each section.
• Non-functional: Do not store or transmit API keys outside OpenCode/OpenCode Go endpoints. Do not mutate OpenCode auth files.

Architecture

Create an OpenCode Go credential source that reads OpenCode's auth store and a provider implementation that maps verified weekly/monthly usage percent + reset time into a provider-specific snapshot. Do not force OpenCode Go into the existing UsageWindows.primary/secondary shape if that would lose the grouped weekly/monthly rendering semantics.

Related Code Files

• Create: src/creds/opencode_auth.rs
• Create: src/usage/opencode_go.rs
• Modify: src/creds/mod.rs
• Modify: src/usage/mod.rs
• Modify: src/usage/registry.rs
• Modify: src/usage/refresh.rs
• Modify: src/app.rs

Implementation Steps

1. Add LocalOpenCodeGoCreds with path detection from Phase 1. Expected primary path: %LOCALAPPDATA%/XDG-equivalent for opencode/auth.json; verify exact Windows path before coding.
2. Parse only the OpenCode Go auth entry. Support API-key style auth if Phase 1 confirms schema.
3. Add RefreshHint::LocalOpenCodeCli and spawn opencode auth login or equivalent only if Phase 1 confirms the command.
4. Add OpenCodeGoProvider::poll, using the verified usage endpoint/command.
5. Add a provider-specific snapshot type if needed, for example ProviderUsage::TwoWindow(UsageWindows) and ProviderUsage::WeeklyMonthly { weekly: Window, monthly: Window }.
6. Map returned weekly/monthly source data to usage percent and reset-time windows. Existing renderer can then draw usage and remaining-time bars for each window.
7. Return AuthRequired on 401/403 or missing provider auth.
8. Add unit tests for credential parsing and response-to-snapshot mapping.

Success Criteria

• Provider compiles behind the existing registry.
• Missing OpenCode auth produces NoCredentials, not panic.
• Expired/invalid auth produces AuthRequired.
• Weekly/monthly usage percent clamps to 0-100 and remaining-time bars derive from verified reset times.
• If Phase 1 cannot verify usage, this phase is not implemented.

Risk Assessment

OpenCode Go limits are dollar-value based. If the usage source returns dollars instead of percentages, compute percent only as used / limit * 100 from server-provided weekly/monthly values. Never estimate usage from model prices. If reset times are unavailable, stop and ask before shipping remaining-time bars with guessed periods.