feat: promptable config — detect missing keys and collect values conversationally

[sentry-junior]

Summary

Today, junior config is set only via explicit jr-rpc config set commands. Config values should also be settable through natural-language prompting — similar to how Claude Code uses CLAUDE.md to establish per-project behavior — so any capability that needs configurable input can acquire it conversationally.

Current Behavior

• Config is set exclusively via jr-rpc config set <key> <value> shell commands.
• Skills and tools that need config values (e.g. github.repo) require the user to have already set them manually.
• No mechanism exists to detect missing config and prompt the user to supply it mid-conversation.

Gap / Opportunity

• Users shouldn't need to know which config keys exist before using a skill; the assistant should detect the gap and ask.
• Conversational config sets a lower barrier to entry and matches how people naturally interact with Slack bots.
• Aligns with the Claude Code model: behavior is shaped by prompts/files, not just CLI flags.

Prior Art

• Claude Code CLAUDE.md — repo-level markdown file that shapes model behavior for a project; effectively "promptable config" at file scope. No direct URL available; described in Claude Code docs at code.claude.com/docs/en/settings.
• Slack bot onboarding flows — common pattern where bots ask setup questions inline and persist answers, rather than requiring upfront CLI config.

Options

• Option A — Inline prompt on missing config: when a skill detects a required config key is absent, pause and ask the user for the value, then set it via jr-rpc config set and continue. Minimal surface change; works for any skill.
• Option B — Natural-language config parsing: allow freeform statements like "use getsentry/sentry for all issues" to be parsed and persisted as config, even without an explicit command invocation. Higher complexity; requires intent classification.

Recommended Direction

Start with Option A: required-key detection + inline prompt + auto-persist. This covers the core gap with low risk and makes Option B a natural follow-on once the persist path is proven.

Acceptance Criteria

• When a skill requires a config key that is not set, junior prompts the user for the value inline.
• User-supplied value is persisted via jr-rpc config set and the skill resumes without re-invocation.
• Works for any config key, not just github.repo.
• Natural-language phrasing ("use repo X") is recognized and stored as config without requiring /config set.

Risks

• Prompting mid-skill adds a turn of latency; mitigation: only block on truly required keys, not optional ones.
• Misclassifying a statement as a config intent could silently overwrite existing config; mitigation: confirm before persisting on ambiguous input.

Sources

• Claude Code settings reference: https://code.claude.com/docs/en/settings
• Current junior config implementation: getsentry/junior (channel config via jr-rpc)