Session recap · agentics · 2026-07-02

Building the export-session skill, from one-off to shipped plugin

One session took a single request — “export sessions as Markdown so they can teach” — through four shapes: standalone skill, standalone plugin, a skill folded into social-media-tools, and finally a reviewed, hardened pull request.

What the skill produces

Every export opens with frontmatter like this — the recap you are reading borrows the format.

---
session-id: "5f240d94-3602-4f95-8b49-e69764d87b9f"
date: 2026-07-02
source: "~/.claude/projects/-Users-shawnsandy-devbox-agentics/…jsonl"
type: session-export
---
# then: user / Claude turns, tool calls as one-liners, harness noise removed

How the session unfolded

Skill first, script-backed

Built export-session as a project skill: a SKILL.md workflow plus export_session.py, so multi-megabyte JSONL transcripts are converted by Python and never enter model context. First smoke test exposed harness noise (<local-command-caveat>) leaking into output; fixed with a prefix blocklist.

Promoted to a plugin

Repackaged as a session-tools marketplace plugin (0.1.0) — manifest, README, CHANGELOG, marketplace registration at 4.1.0 — using ${CLAUDE_PLUGIN_ROOT} so the script path survives installation anywhere.

Folded into social-media-tools

The one-skill plugin dissolved: export-session moved beside its sibling share-session, which already reads the same transcripts. Expressed as a minor bump (2.13.0 → 2.14.0); the marketplace returned to 4.0.0 with 11 plugins. The skill needed zero content changes to move.

PR, review, hardening

Opened PR #368. Copilot's review surfaced four legitimate findings; all fixed in one pass, replied to, and resolved. Rate-limited bot posts from Codex and CodeRabbit were correctly treated as non-findings.

What shipped

kit/plugins/social-media-tools/skills/export-session/SKILL.mdworkflow + discovery

…/export-session/scripts/export_session.pyJSONL → Markdown

kit/plugins/social-media-tools/CHANGELOG.mdv2.14.0 entry

.claude-plugin/marketplace.json2.13.0 → 2.14.0

docs/plans/add-export-session-skill.mdplan, completed

CLAUDE.md · plugin READMEdiscovery surfaces

Review findings, all fixed in 3a56b99

Finding	Fix
Filename collisions	Short session-id suffix: `<date>-<slug>-<sid8>.md` — unique across sessions, idempotent per session (proved by exporting twice → one file)
Unquoted YAML	`session-id` and `source` now JSON-quoted in frontmatter
Whole-file read	Transcript streams line-by-line with explicit UTF-8
Noisy glob	Discovery command silences stderr when no sessions exist yet

By the numbers

Pull request

#368

Commits

Smoke-test turns

264

Review threads resolved

4 / 4

Worth remembering

Scripts over context: converting transcripts in Python keeps the model from ever reading megabytes of JSONL — the skill just locates the file and shells out.
Domain-container naming resolved itself: the standalone plugin lasted one commit before the skill found its real home next to share-session.
Unshipped versions are free: because 2.14.0 and 4.1.0 never reached main, the restructure cost nothing — no compatibility story, just cleaner history.
Idempotent filenames beat counters: a session-id suffix makes re-exports overwrite themselves instead of piling up -2, -3 duplicates.