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/jamestelfer/sandy/clinpx skills add jamestelfer/sandy --skill cligit clone --depth 1 https://github.com/jamestelfer/sandyWhat 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 | $0.00045 | $0.01703 |
| Opus 5 | $0.00023 | $0.00851 |
| Sonnet 5 | $0.00009 | $0.00341 |
| Haiku 4.5 | $0.00005 | $0.00170 |
Grade A, and why
sandy 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 — 189 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Sandy
Sandy executes TypeScript scripts in disposable sandboxed environments (Shuru microVMs or Docker containers) with AWS credentials from IMDS.
The CLI uses explicit sessions. Create one first, then run scripts from that session’s scripts/ directory.
Setup
Read the scripting guide before writing scripts:
sandy resource sandy://skills/cli/resources/scripting-guide.md
This guide defines runtime constraints, available AWS SDK packages, and the required async generator pattern.
IMDS port
Start an IMDS server separately and pass its port to sandy run and sandy check connect.
CLI commands
sandy image
Create or delete the Sandy sandbox image.
sandy image create
sandy image delete
sandy image delete --force
sandy session create
Create a session and print the session name plus scripts path.
sandy session create
sandy check
Verify sandbox health. Each check creates and deletes an ephemeral session; no session argument is accepted.
sandy check baseline
sandy check connect --imds-port 9001
sandy check connect --imds-port 9001 --region ap-southeast-2
sandy run
Run a TypeScript script from <session>/scripts/.
sandy run --session happy-fox-trail --script inventory.ts --imds-port 9001
sandy run --session happy-fox-trail --script inventory.ts --imds-port 9001 --region ap-southeast-2
sandy run --session happy-fox-trail --script inventory.ts --imds-port 9001 -- arg1 arg2
Options:
| Flag | Required | Description |
|---|---|---|
--session |
yes | Session name |
--script |
yes | Script path relative to <session>/scripts/ |
--imds-port |
yes | Port of the running IMDS server |
--region |
no | AWS region (default us-west-2) |
-- |
no | Arguments passed as process.argv inside the script |
Session layout on the host:
.sandy/<session>/scripts/mounted read-only at/workspace/scripts.sandy/<session>/output/mounted read-write at/workspace/output
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 189 lines · 45 tokens per session scan A 496a783f889a
sandy is a skill published in the GitHub repository jamestelfer/sandy (7 stars, last pushed 28d ago), licensed Apache-2.0. It adds 45 tokens to every session and 1,703 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.
Other skills, from other repositories
cognito-passkey-auth
Amazon Cognito — Custom UI with Passkeys, Social Login & Face ID. Reference skill (loaded via skill:// from the ios agent).
amazon-location-service
Amazon Location Service. Reference skill (loaded via skill:// from the ios agent).
amazon-polly-generative
Amazon Polly Generative Voices. Reference skill (loaded via skill:// from the ios agent).
aws-cdk
AWS CDK infrastructure development in TypeScript. Use when creating stacks, constructs, L2/L3 patterns, CDK testing, synth/deploy pipelines or organizing IaC code.
aws-lambda-typescript
AWS Lambda development with TypeScript. Use when writing Lambda handlers, bundling with esbuild, using AWS SDK v3/Powertools, strict typing or optimizing Node.js Lambda performance.
aws-serverless
Building production-ready serverless applications on AWS. Use when working with Lambda, API Gateway, SQS, SNS, DynamoDB Streams, SAM/CDK deployment or optimizing cold starts.