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/error-trackernpx skills add fullstack-phoenix/saas_kit --skill error-trackergit 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 | $0.00042 | $0.00902 |
| Opus 5 | $0.00021 | $0.00451 |
| Sonnet 5 | $0.00008 | $0.00180 |
| Haiku 4.5 | $0.00004 | $0.00090 |
Grade A, and why
error-tracker 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 yesterday.
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 — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ErrorTracker
Adds ErrorTracker, an Elixir-native error tracking solution, to a Phoenix app. It stores exceptions in your existing database and serves a LiveView dashboard for reviewing, resolving, muting, and inspecting occurrences — no external service or hosted account required. Phoenix controllers, LiveViews, and Oban jobs report automatically.
When to use
- The app needs to capture and review production exceptions but you don't want Sentry/AppSignal or another hosted error service.
- You want stack traces, occurrences, breadcrumbs, and context stored alongside your own data in your existing repo.
- Don't reach for this if you already pipe errors to a hosted tracker — running
both duplicates noise. For a no-dashboard setup, plain
Loggermay suffice.
Dependencies
- Requires: None.
- Recommended:
admin(mounts the dashboard under/admin/errorsand links it from the developer page),oban(adds job metadata to error context).
Install
mix saaskit.feature.install error_tracker
No install decisions. The mount point is chosen automatically:
- With the
adminfeature installed → dashboard at/admin/errors, linked from the admin developer page. - Without
admin→ dashboard mounted beside the development LiveDashboard route.
What it generates
- Adds
{:error_tracker, "~> 0.9.0"}tomix.exsdeps. - Config block in
config/config.exs(see Configuration). - Migration
priv/repo/migrations/*_add_error_tracker.exs— delegates toErrorTracker.Migration.up/0to create the error tracker tables. lib/my_app_web/router.ex— injectsuse ErrorTracker.Web, :routerand theerror_tracker_dashboard "/errors"route at the appropriate mount point.
Configuration
Injected at the top of config/config.exs:
# config/config.exs
config :error_tracker,
otp_app: :my_app,
repo: MyApp.Repo,
enabled: Mix.env() != :test,
plugins: [ErrorTracker.Plugins.Pruner]
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.
- yesterday First seen · 113 lines · 42 tokens per session scan A ebf6c4741636
error-tracker is a skill published in the GitHub repository fullstack-phoenix/saas_kit (2 stars, last pushed 2mo ago), licensed MIT. It adds 42 tokens to every session and 902 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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