[FEATURE] Disclose per-turn token cost of reactions + opt-out during setup

[Nipeno]

What would you like?

Two small things around reactions transparency:

1. A note in the README (near the install steps) that reactions add tokens to every response — the MCP server instructs Claude via system prompt to append <!-- buddy: ... --> at the end of every turn, which means every session has ongoing token overhead even when the user isn't interacting with the buddy directly.
2. A prompt during install asking whether to enable reactions, or make them opt-in by default. There's already a /buddy off command, but it requires the user to discover it after the fact.

Why?

Users coming from the original /buddy may not expect the MCP version to affect token usage — the original was purely a display feature. Right now nothing in the README or install flow warns about this, so users on paid plans or with tight budgets may accumulate unexpected cost before they notice.

Ideas for implementation

• Add one line to the README under install: something like "Reactions are enabled by default and add a small number of tokens per turn. Run /buddy off to disable."
• Optionally, add a y/N prompt to the setup wizard: Enable reactions? Buddy will comment on your code each turn (adds ~20–50 tokens per response)

Not asking to change the default necessarily — just surfacing it so users can make an informed choice before their first session.

[iilonmasc]

Info from @1270011 from issue #12

Token estimate: roughly ~1.5k tokens at startup (MCP tool definitions + instructions + skill) and ~20 tokens per response (the buddy's comment). Over a full 50-turn session that's about 2.5k tokens total — somewhere around 1% of a typical session. Not a completely free meal, but 1% of a 5-hour session window means you lose about 3 minutes worth of tokens.

I guess this would suffice in the README as an estimate?

[r0bis]

One thing which is not completely understandable in in the readme - if turning the off buddy via /buddy off would stop token usage. The explanation is just "Mute / unmute reactions" which implies continued the interaction with claude, just hiding it. From readme as of now it appears as if one has to go out of claude, into the terminal and do bun run disable which then would "Temporarily deactivate buddy". But even there it is not crystal clear if it would stop token use when claude is started again.