Borrowing it
Nothing to install: this file belongs to KhaledSaeed18/node-express-boilerplate. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/KhaledSaeed18/node-express-boilerplate/main/.github/instructions/typescript-assertions.instructions.mdgit clone --depth 1 https://github.com/KhaledSaeed18/node-express-boilerplateWrote 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/instructions/khaledsaeed18/node-express-boilerplate/typescript-assertions)<a href="https://agentmods.dev/instructions/khaledsaeed18/node-express-boilerplate/typescript-assertions"><img src="https://agentmods.dev/badge/instructions/khaledsaeed18/node-express-boilerplate/typescript-assertions/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/instructions/khaledsaeed18/node-express-boilerplate/typescript-assertions"><img src="https://agentmods.dev/badge/instructions/khaledsaeed18/node-express-boilerplate/typescript-assertions.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 | $0.00344 | $0.00344 |
| Opus 5.5 | $0.00138 | $0.00138 |
| Sonnet 5.5 | $0.00069 | $0.00069 |
| Haiku 4.5 | $0.00034 | $0.00034 |
Grade A, and why
node-express-boilerplate typescript-assertions.instructions.md 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 1mo 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.
What it actually says
TypeScript Assertion Safety
Follow this file when touching TypeScript in src/ where merges can introduce assertion-heavy fixes.
Rule
- Treat type assertions as a last resort.
- Prefer control-flow narrowing, user-defined type guards,
satisfies, andas const+typeofderivation. - Do not use double assertions (
as unknown as T) unless there is no safe alternative and the boundary is documented.
Preferred Patterns
- Runtime-to-type derivation:
- Define constants with
as const. - Derive unions with
typeof Obj[keyof typeof Obj].
- Define constants with
- External input handling:
- Validate and narrow first, then use strongly typed values.
- Framework interop edge cases (Express/Node APIs):
- Use narrow casts on the smallest expression, not on wide objects.
Merge-Fix Checklist
- Remove newly added broad casts and replace with narrowing where possible.
- Keep assertions local to integration boundaries.
- Ensure final code passes the project quality gate in AGENTS.md.
References
- Project-wide standards: AGENTS.md
- Copilot wrapper: .github/copilot-instructions.md
- Assertion derivation examples: .agents/skills/typescript-magician/rules/as-const-typeof.md
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.
- 1mo ago First seen · 36 lines · 344 tokens per session scan A 12254ba10340
node-express-boilerplate typescript-assertions.instructions.md is an instructions file published in the GitHub repository KhaledSaeed18/node-express-boilerplate (36 stars, last pushed yesterday), licensed MIT. It adds 344 tokens to every session, about $0.0014 per session on Opus 5.5. 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 2026-08-30.
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