Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/fullstack-phoenix/saas_kit/paper-trailnpx skills add fullstack-phoenix/saas_kit --skill paper-trailgit clone --depth 1 https://github.com/fullstack-phoenix/saas_kitWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00044 | $0.01093 |
| Opus 5 | $0.00022 | $0.00547 |
| Sonnet 5 | $0.00009 | $0.00219 |
| Haiku 4.5 | $0.00004 | $0.00109 |
Grade A, and why
paper-trail scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 119 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Versions with Paper Trail
Adds automatic record versioning via the paper_trail
library. Every insert, update, and delete you route through PaperTrail is written
to a versions table, so you can audit how a record changed over time, attribute
each change to a user, and revert a record to an earlier state.
When to use
- You need an audit log of changes to specific schemas (compliance, debugging).
- You want "undo" — the ability to revert a record to a previous version.
- You need to know which user made a given change.
- Don't reach for this if you only need created/updated timestamps — Ecto's
timestamps()already covers that. Versioning adds a row per change.
Dependencies
- Requires: None.
- Recommended:
authentication— the migration references theuserstable for the originator, and the admin browser maps"User" => MyApp.Users.User.
Install
mix saaskit.feature.install paper_trail
No installer decisions. The admin-only instructions (a nav item, a /admin/versions
route, and the version browser LiveView) are applied only if the admin feature
is present.
What it generates
- Adds
{:paper_trail, "~> 1.1.0"}tomix.exs. - Migration
priv/repo/migrations/*_add_versions.exs— creates theversionstable (event,item_type,item_id,item_changes,originator_id,origin,meta,inserted_at). lib/my_app/versions.ex—get_versions/1,revert_to_version/2, and the change-diffing helpers behind revert.- Wraps
lib/my_app/repo.exwithinsert_with_papertrail/2,update_with_papertrail/2,delete_with_papertrail/2, which return the plain model ({:ok, model}) instead of PaperTrail's%{model: ...}map. test/my_app/versions_test.exs.- With
admin:lib/my_app_web/live/admin/version_live/show.ex(the/admin/versionsbrowser), a route, and a "Versions" nav item.
Configuration
Injected into config/config.exs:
config :paper_trail,
repo: MyApp.Repo,
timestamps_type: :utc_datetime
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 119 lines · 44 tokens per session scan A 04ae61973274
paper-trail is a skill published in the GitHub repository fullstack-phoenix/saas_kit (2 stars, last pushed 2mo ago), licensed MIT. It adds 44 tokens to every session and 1,093 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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