qb-linq: Skill for Cursor

.cursor/skills/qb-linq-development/SKILL.md

qb-linq-development is a skill for Cursor from isndev/qb-linq. It costs 69 tokens per session (666 once invoked), scanned A, original, MIT.

A development guide for qb-linq, a header-only C++17 library for building data-processing queries. It covers the library’s query pipelines, iterators, lazy views, tests, and benchmarks.

In plain words
What is it for?
Extend or debug qb::linq, add query operations and views, update tests, build the CMake targets, and run benchmarks when needed.
Why use it?
It helps contributors find the correct declarations and implementations and avoid breaking the library’s iterator or materialization behavior.

Skill for Cursor

Written for Cursor: installed under .cursor/. Also seen: mentions AGENTS.md.

This is isndev/qb-linq's own configuration. It tells Cursor how to work on qb-linq itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything qb-linq configures →

Reuse

Borrowing it

Nothing to install: this file belongs to isndev/qb-linq. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/isndev/qb-linq/main/.cursor/skills/qb-linq-development/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/isndev/qb-linq

Made for: Cursor.

Wrote 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.

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README.md
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Your own site
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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.

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Your own site · 80×15
<a href="https://agentmods.dev/skills/isndev/qb-linq/qb-linq-development"><img src="https://agentmods.dev/badge/skills/isndev/qb-linq/qb-linq-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 666 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00069 $0.00666
Opus 5 $0.00034 $0.00333
Sonnet 5 $0.00014 $0.00133
Haiku 4.5 $0.00007 $0.00067

Measured 9d ago against content hash 0a0ca338389f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

qb-linq-development 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.

.cursor/skills/qb-linq-development/SKILL.md · 43 lines

How it starts

The opening of the file, as written. The whole thing — 43 lines — stays where its author put it; the contents beside it link to each section on GitHub.

qb-linq development

When this applies

Use this skill for work inside the qb-linq repository: changing pipelines, iterators, materializers, tests, or benchmarks—not for application code that only consumes qb::linq::from(...).

Required context (read first)

  1. docs/BUILDING.md — CMake target qb::linq, options, presets, qb_linq_tests / qb_linq_benchmark / qb_linq_docs.
  2. docs/LLM_CONTEXT.md — include graph, handle types, out-of-line split (query.h vs extra_views.h), materialized_range pitfall.
  3. AGENTS.md — checklist and file map.
  4. include/qb/linq.h — Doxygen linq group: public caveats.
  5. CONTRIBUTING.md — tests, PR checklist, CHANGELOG for user-visible changes.

Workflow

  1. Locate the API — Methods on enumerable trace to query_range_algorithms in query_range.h.
  2. Declaration vs definition — Declarations in query_range.h; definitions in query.h or extra_views.h per LLM_CONTEXT.md.
  3. New iterators — Extend patterns in iterators.h or extra_views.h; respect iterator category rules (clamp_iterator_category_t where appropriate).
  4. Verify — Build qb_linq_tests, run ctest. For perf-sensitive code, enable QB_BUILD_BENCHMARKS and keep qb_linq_benchmark building.
  5. Portability — Validate on multiple compilers when possible (GCC, Clang, MSVC).

Pitfalls

  • Do not break materialized_range safe construction documented in query.h.
  • select_many yields a tuple of projections per element, not a flattened sequence (not C# SelectMany).
  • scan_iterator must not outlive scan_view (F* into the view).
  • reverse() + take / take_while: use the dedicated reversed_view specializations in query.h; new logical-end iterators must not break reverse_iterator equality or bounds.

Output expectations

  • Minimal diffs, consistent style and Doxygen.
  • Tests for behaviour changes.
  • English commit messages; state what and why.

Read the full file on GitHub · 43 lines

Changes

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.

  1. 9d ago First seen · 43 lines · 69 tokens per session scan A 0a0ca338389f

Subscribe to this mod's changes

qb-linq-development is a skill published in the GitHub repository isndev/qb-linq (13 stars, last pushed 9d ago), licensed MIT. It adds 69 tokens to every session and 666 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 2026-08-30.

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