tapes start codex requires manual API key configuration

[bdougie]

Problem

When running tapes start codex, users must manually set the OPENAI_API_KEY environment variable. There is no login mechanism or credential storage, making it inconvenient for users who want to run Codex without managing environment variables.

Current Behavior

• tapes start codex launches the Codex agent
• Codex requires an OpenAI API key to function
• Users must set OPENAI_API_KEY in their shell environment before running the command
• No way to store or manage API credentials within tapes

Expected Behavior

• Users should be able to run tapes start codex without needing to manually configure OPENAI_API_KEY
• Implement a login mechanism (e.g., tapes login) to securely store API keys
• Auto-inject stored credentials when launching agents

Implementation Approach

1. Add credential storage to config (alongside existing config.toml)
2. Create a tapes login command to store API keys securely
3. Modify tapes start codex to inject stored credentials via environment variables
4. Support per-provider API keys (OpenAI for Codex, Anthropic for Claude, etc.)

Related Issues

• Improve opencode agent startup DX with provider and model selection #89 - Improve opencode agent startup DX with provider and model selection (depends on this)

Related Branch

• feat/tapes-start-agents - Initial agent startup framework

Related Code

• Agent startup: cmd/tapes/start/start.go:152-219
• Config structure: pkg/config/types.go
• Config storage: pkg/config/config.go

[linear]

PCC-104