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 skills add JustineDevs/premortem --skill nango-toolboxgit clone --depth 1 https://github.com/JustineDevs/premortemWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/justinedevs/premortem/nango-toolbox)<a href="https://agentmods.dev/skills/justinedevs/premortem/nango-toolbox"><img src="https://agentmods.dev/badge/skills/justinedevs/premortem/nango-toolbox/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/justinedevs/premortem/nango-toolbox"><img src="https://agentmods.dev/badge/skills/justinedevs/premortem/nango-toolbox.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What 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 5.1 | $0.00057 | $0.01099 |
| Opus 5 | $0.00028 | $0.00549 |
| Sonnet 5 | $0.00011 | $0.00220 |
| Haiku 4.5 | $0.00006 | $0.00110 |
Grade A, and why
nango-toolbox 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 9d 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 — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.
When to use
- Any access to an external API.
- External API calls must go through Nango.
- Do not use MCPs, provider CLIs, or ad-hoc direct API calls outside Nango.
Configuration (required)
Resolve values in this order.
Secret key
NANGO_TOOLBOX_SECRET_KEYin the process environmentNANGO_TOOLBOX_SECRET_KEYin a local.env
If missing, ask the user to:
- create a Nango account: https://app.nango.dev/signup
- copy the secret key from Environment settings → Backend
- set
NANGO_TOOLBOX_SECRET_KEYin their shell profile (offer to add it)
Compatibility: if other instructions refer to NANGO_SECRET_KEY, treat it as NANGO_TOOLBOX_SECRET_KEY.
Base URL
NANGO_SERVER_URLin the process environmentNANGO_SERVER_URLin a local.envhttps://api.nango.dev
HTTP headers
Authorization: Bearer <NANGO_TOOLBOX_SECRET_KEY>Content-Type: application/json- Prefer JSON bodies over query params when both exist.
Discovery (use these first)
List integrations:
GET <base-url>/integrations
Authorization: Bearer <secret-key>
List connections for an integration:
GET <base-url>/connections?integrationId=<unique_key>
Authorization: Bearer <secret-key>
List deployed actions/syncs:
GET <base-url>/scripts/config
Authorization: Bearer <secret-key>
Choose integration (do this before connection)
- Check if an integration for your API is setup in Nango
- If not, set it up for the user:
- If the API is OAuth and has Nango provided developer credentials, ask the user to enable it manually in the dashboard.
- If the API is OAuth and doesn't have Nango developer credentials guide the user to get a client id & secret
- If the API uses "OAuth client credentials", do not ask the user for client id & secret. Set the integration up and the user will enter them with the Connect Link.
- In all other cases, set the integration up and proceed with creating a Connect link
Do not ask the user for any Connection specific parameters. Always let it enter these in the Connect link.
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.
- 9d ago First seen · 137 lines · 57 tokens per session scan A a7fc6cb04ba0
nango-toolbox is a skill published in the GitHub repository JustineDevs/premortem (2 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 57 tokens to every session and 1,099 once invoked, about $0.0003 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 2026-09-03.
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