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 Robotti-io/copilot-security-instructions --skill input-validation-hardeninggit clone --depth 1 https://github.com/Robotti-io/copilot-security-instructionsWrote 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/robotti-io/copilot-security-instructions/input-validation-hardening)<a href="https://agentmods.dev/skills/robotti-io/copilot-security-instructions/input-validation-hardening"><img src="https://agentmods.dev/badge/skills/robotti-io/copilot-security-instructions/input-validation-hardening.svg" alt="Measured on agentmods" 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 | $0.00024 | $0.00416 |
| Opus 5 | $0.00012 | $0.00208 |
| Sonnet 5 | $0.00005 | $0.00083 |
| Haiku 4.5 | $0.00002 | $0.00042 |
Grade A, and why
input-validation-hardening 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 8d 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
Input Validation Hardening
When to use
Use this skill when asked to validate inputs, harden request parsing, or prevent injection/abuse.
Inputs to collect (if available)
- Entry points (HTTP endpoints, consumers, file parsers)
- Data sensitivity and trust boundaries
- Existing validation libraries/patterns in the codebase
- Known attack/abuse cases (payloads, bypass attempts)
Step-by-step process
- Inventory inputs
- HTTP params/body/headers, file uploads, message payloads, env vars, CLI args
- Define schemas
- Prefer typed schemas (DTOs) and allow-lists
- Enforce length, charset, ranges, and required fields
- Canonicalize early
- Normalize encoding, trim, and apply consistent parsing (dates, IDs, enums)
- Validate before use
- Reject unknown fields if possible
- Ensure IDs map to authorized resources (ownership/tenant checks)
- Protect sinks
- Parameterize DB queries
- Avoid dynamic execution (eval, shell, template injection)
- Add tests
- Boundary tests (min/max), malformed inputs, and common payloads
Output
- Proposed schema(s)
- Where to enforce validation (middleware/controller boundary)
- Tests added/updated
Repo integration (optional)
Related prompts:
validate-input-handling.prompt.mdscan-for-insecure-apis.prompt.md
Output format
- Inventory: inputs and boundaries
- Proposed schema(s) (high-level)
- Enforcement point: where validation should occur
- Test plan: boundary + malicious inputs
Examples
- “Public JSON API” → reject unknown fields, enforce max sizes, and add negative tests for type confusion and oversized payloads.
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.
- 8d ago First seen · 60 lines · 24 tokens per session scan A ff677ebea4b1
input-validation-hardening is a skill published in the GitHub repository Robotti-io/copilot-security-instructions (42 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 24 tokens to every session and 416 once invoked, about $0.0001 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 2026-08-30.
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