docs: capture agent workflow decisions

docs/00 INBOX/ai/tldr-design.md

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+# TL;DR command design
+
+## Goal
+
+Add a Pi command that summarizes the preceding agent response by default.
+An explicit command argument identifies the source to summarize.
+
+## Decision tree
+
+- Command form and scope
+  - Settled: Create a project prompt template at `.pi/prompts/tldr.md`.
+  - Command interface
+    - Settled: Pass arguments through as a free-form source request.
+    - Default source selection
+      - Settled: Summarize the preceding agent response when no source request exists.
+      - Summary format and length
+        - Settled: Use a compact, format-free summary.
+        - Ambiguous-source behavior
+          - Settled: Add no special handling policy.
+
+## Settled decisions
+
+- **Q1 — Command form and scope:** Create a project prompt template.
+- **Q2 — Explicit source interface:** Accept a free-form source request.
+- **Default source selection:** Summarize the preceding agent response when the command has no arguments.
+- **Q3 — Summary shape:** Use a compact, format-free summary.
+- **Q4 — Unavailable source:** Add no special handling policy.
+
+## Frontier
+
+The frontier is empty.
+
+## Shared understanding pending confirmation
+
+The project gets a `/tldr` prompt command in `.pi/prompts/tldr.md`.
+Without arguments, it summarizes the preceding agent response.
+With arguments, it interprets them as a free-form source request.
+It produces a compact summary with no fixed format.
+The prompt adds no special policy for unavailable or unclear sources.