my-pi/pi-permission-system/docs/retro/0045-session-scoped-approvals.md

issue, issue_title

issue	issue_title
45	Add "approve for this session" option to permission prompts

Retro: #45 — Add "approve for this session" option to permission prompts

Final Retrospective (2026-05-03T15:30:00Z)

Session summary

Implemented session-scoped approvals for the external_directory permission surface across plan, TDD, ship, and release (v3.4.0). Four feat commits added SessionApprovalCache, extended the permission dialog with a fourth option, wired the cache into both file-tool and bash external-directory gates, and documented the feature. The TDD cycle caught a deriveApprovalPrefix edge case (trailing-separator paths) on the first red pass.

Observations

What went well

• TDD red→green cycle was clean across all three feature steps. The deriveApprovalPrefix trailing-separator bug (dirname("/other/project/src/") strips the slash and returns the parent) was caught immediately by a failing test — fixed in seconds, no rework.
• Plan-to-implementation fidelity was high. The plan's SessionApprovalCache design, dialog extension, and index.ts wiring mapped 1:1 to the implementation with no structural surprises.
• The applyPermissionGate abstraction (from #41) made the wiring step straightforward — wrapping promptForApproval to capture the decision state was a clean seam.
• Ship and release were fully automated: CI green, release-please PR merged, v3.4.0 tagged.

What caused friction (agent side)

• missing-context — After committing the docs update, I did not proactively confirm that all plan-flagged documents were aligned. The user had to ask "All our documents are up to date?" to trigger verification. Impact: one extra user round-trip, no rework needed (docs were actually complete).
• other (tool fragility) — A multi-edit Edit call on README.md failed on the second edit due to an oldText mismatch with Unicode → characters in the architecture tree. The first edit (session-scoped approvals section) was silently lost. Caught during post-commit verification and fixed by amending the commit. Impact: minor rework (re-applied the edit and amended), ~1 minute.

What caused friction (user side)

• The "All our documents are up to date?" prompt was mechanical oversight — the agent should have provided a verification summary unprompted after the docs commit. No user-side change needed; this is an agent salience issue.