feat(prompt): optimize booking flow with tool chaining, ASAP auto-select, and structured errors

[dhairyashiil]

feat(prompt): optimize booking flow with tool chaining and ASAP auto-select

Summary

Rewrites the booking section of the agent system prompt in lib/agent.ts to minimize user round-trips (from 4 messages → 2 for the best case). Also adds structured error hints to tool returns so the agent can react more intelligently to failures.

Prompt changes (getSystemPrompt()):

• Step 0: Defaults to "theirs" (Option B) when a Cal.com username is present in the message. Only asks "Yours or Theirs?" when genuinely ambiguous.
• Tool chaining: New section instructing the agent to chain tool calls within a single turn (e.g., list_event_types → check_availability → text) instead of stopping after each tool.
• ASAP auto-select: Auto-selects slots[0] for ASAP requests instead of presenting 3-5 options. Uses nextAvailableSlots from the extended search when 0 slots found in 3 days.
• Option B fallback: When username lookup fails, offers to switch to Option A (user's own calendar) with attendee name+email.
• Username ambiguity: Guides the user to share a direct booking link when the wrong person's event types are returned.
• Fast-path scoping: Explicitly limits skip-confirmation fast-path to Option A only. Option B always requires confirmation.

Tool return changes:

• list_event_types_by_username: Adds fallbackSuggestion on 0 results and retryable + fallbackSuggestion on errors.
• book_meeting / book_meeting_public: Adds retryable and suggestion fields for 409 conflicts and network errors.

Review & Testing Checklist for Human

These are prompt-engineering changes — CI passing confirms types/lint only, not behavioral correctness. Manual testing is required.

• Test "book with X asap" (1 event type): Verify the agent chains list_event_types_by_username → check_availability_public → confirmation text in a single turn (2 user messages total)
• Test "book with X asap" (multiple event types): Verify the agent stops to ask which event type, then auto-selects earliest slot (3 messages)
• Test username not found: Verify the fallback message offers Option A with name+email
• Test Option B always confirms: Send "book with peer asap, just do it" — agent should still ask for confirmation (no fast-path for Option B)
• Test Option A fast-path preserved: Send "book a 30 min with john@example.com tomorrow 2pm, just do it" — should book without confirmation
• Verify non-booking flows unaffected: Cancel, reschedule, "am I free?", schedule management should all work as before (the prompt sections for these were not modified)
• Review error string matching in the catch blocks — the isConflict/isNetwork heuristics rely on substring matching ("409", "conflict", "fetch", "timeout") which may not cover all real API error formats

Notes

• All changes are in a single file: apps/chat/lib/agent.ts
• No API changes, no handler changes, no schema changes
• The error hint fields (retryable, suggestion, fallbackSuggestion) are additional return object properties — no schema enforcement, the agent reads them as context

Link to Devin session: https://app.devin.ai/sessions/f0604c789fbb43299f2dc7ba90c4616b
Requested by: @dhairyashiil

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[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="apps/chat/lib/agent.ts">

<violation number="1" location="apps/chat/lib/agent.ts:795">
P2: The fallback string `"Failed to fetch event types for this user"` contains `"fetch"`, so `isNetwork` is always `true` when `err` is not an `Error` instance. This misclassifies unknown errors as transient network failures, giving the agent a misleading retry hint.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

1 issue found across 1 file (changes from recent commits).

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="apps/chat/lib/agent.ts">

<violation number="1" location="apps/chat/lib/agent.ts:1130">
P2: Generic fetch failures are no longer classified as retryable network errors in the booking tools.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

1 issue found across 1 file (changes from recent commits).

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="apps/chat/lib/agent.ts">

<violation number="1" location="apps/chat/lib/agent.ts:795">
P2: This narrower check stops retryable Cal.com lookup failures from being recognized, so transient 5xx errors get reported to the agent as an invalid username.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}