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.
git clone --depth 1 https://github.com/launchdarkly-labs/cursor-rulesWrote 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/rules/launchdarkly-labs/cursor-rules/using-flags)<a href="https://agentmods.dev/rules/launchdarkly-labs/cursor-rules/using-flags"><img src="https://agentmods.dev/badge/rules/launchdarkly-labs/cursor-rules/using-flags/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/rules/launchdarkly-labs/cursor-rules/using-flags"><img src="https://agentmods.dev/badge/rules/launchdarkly-labs/cursor-rules/using-flags.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 | $0.00006 | $0.00334 |
| Opus 5.5 | $0.00002 | $0.00134 |
| Sonnet 5.5 | $0.00001 | $0.00067 |
| Haiku 4.5 | $0.00001 | $0.00033 |
Grade A, and why
using-flags 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
Rule 1: LaunchDarkly Evaluation Must Be Centralized
- All variation and variationDetail calls must go through a shared evaluation function.
This wrapper must:
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Use the singleton instance
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Support mock/local overrides for development/testing
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Enable optional instrumentation (e.g., metrics, logging)
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Evaluation must occur as close as possible to where the flag value is used to support accurate flag status tracking.
Rule 2: LaunchDarkly Context Object Standards
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Applications must document how context objects are constructed, including attribute sources.
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Context objects:
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Must have high cardinality (e.g., user ID, session ID)
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Must not contain or be derived from PII (e.g., don’t hash emails)
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Shared utilities should exist for creating context objects from application-specific data (e.g., createLDContextFor(userObject)).
Rule 3: LaunchDarkly Context Custom Attributes
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Must include attributes that support release strategies:
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Build version or commit SHA
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Session ID or device ID
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Developer identifier or PR ID in ephemeral environments
Client-side SDKs must:
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Avoid frequent identify() or re-initialization calls
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Use state transitions (e.g., anonymous → authenticated) to manage identity
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Cache timestamps may be included
Rule 4: LaunchDarkly Flag Evaluation Predictable Fallback Behavior
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Applications must handle fallback values deterministically.
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Avoid using allFlags() in production due to inconsistent behavior across SDKs.
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Fallbacks should always be passed to variation()/variationDetail() and tested in implementation.
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 · 56 lines · 6 tokens per session scan A 5d738ee2b22e
using-flags is a cursor rule published in the GitHub repository launchdarkly-labs/cursor-rules (2 stars, last pushed 6mo ago), licensed MIT. It adds 6 tokens to every session and 334 once invoked, about $0.0000 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 2026-08-31.
Other cursor rules, from other repositories
code-optimization
Guidelines for optimizing duplicate and poorly structured code.
monitoring
Monitoring, observability, and alerting rules.
documentation-standards
Documentation standards for code, APIs, and architecture.
data-fetching
Data fetching patterns with TanStack Query, Server Components, and Supabase.
new_features
Guidelines for integrating new features into the Task Master CLI.
utilities
// ✅ DO: Create focused, reusable utilities /.