Chdb Datastore
vemetric/vemetric
A skill your agent uses when the user has tabular data (pandas DataFrame, parquet, csv, Arrow, json) and wants to filter, group, aggregate, join, or speed up slow pandas.
Check a diff for code that reinvents something Polar already has — a kit helper, a shared Pydantic type, a repository method, an Orbit component, an existing model property.
Install Reuse Check
$ npx skills add polarsource/polar --skill reuse-check -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install polarsource/polar reuse-check --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/polarsource/polar.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/reuse-check .claude/skills/reuse-check && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "reuse-check" agent skill from https://github.com/polarsource/polar/tree/main/.agents/skills/reuse-check into .claude/skills/reuse-check/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "reuse-check", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/polarsource/polar/tree/main/.agents/skills/reuse-checkType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add polarsource/polar --skill reuse-check -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install polarsource/polar reuse-check --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/polarsource/polar.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/reuse-check .agents/skills/reuse-check && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "reuse-check" agent skill from https://github.com/polarsource/polar/tree/main/.agents/skills/reuse-check into .agents/skills/reuse-check/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "reuse-check", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add polarsource/polar --skill reuse-check -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install polarsource/polar reuse-check --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/polarsource/polar.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/reuse-check .cursor/skills/reuse-check && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "reuse-check" agent skill from https://github.com/polarsource/polar/tree/main/.agents/skills/reuse-check into .cursor/skills/reuse-check/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "reuse-check", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/polarsource/polar.git --path .agents/skills/reuse-check--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add polarsource/polar --skill reuse-check -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install polarsource/polar reuse-check --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/polarsource/polar.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/reuse-check .gemini/skills/reuse-check && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "reuse-check" agent skill from https://github.com/polarsource/polar/tree/main/.agents/skills/reuse-check into .gemini/skills/reuse-check/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "reuse-check", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install polarsource/polar reuse-checkInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add polarsource/polar --skill reuse-check -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/polarsource/polar.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/reuse-check .github/skills/reuse-check && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "reuse-check" agent skill from https://github.com/polarsource/polar/tree/main/.agents/skills/reuse-check into .github/skills/reuse-check/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "reuse-check", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add polarsource/polar --skill reuse-check -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install polarsource/polar reuse-check --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/polarsource/polar.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/reuse-check .opencode/skills/reuse-check && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "reuse-check" agent skill from https://github.com/polarsource/polar/tree/main/.agents/skills/reuse-check into .opencode/skills/reuse-check/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "reuse-check", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
reuse-check- GitHub stars
- 10k
- Token cost
- ~1.2k tokens
- SKILL.md length
- 434 words
- Files
- 1
- Skills in repo
- 18
- Repo updated
- First seen
- Licence
- MIT
At a glance
Check a diff for code that reinvents something Polar already has — a kit helper, a shared Pydantic type, a repository method, an Orbit component, an existing model property.
- Works in 3 steps: Name search — rg -n "def |\b"… → Behaviour search — the distinctive part… → Inventory — check the list below.
- Asks whether a new helper
- SKILL.md covers Scope, Method, Inventory and Output
- Calls rg
What it does
Reuse Check is an agent skill from polarsource/polar. Check a diff for code that reinvents something Polar already has — a kit helper, a shared Pydantic type, a repository method, an Orbit component, an existing model property. Use before opening a PR, when reviewing a diff, or when the user asks whether a new helper, validator, type or utility already exists in the codebase.
Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Data & Analytics, covering DataFrames. It works with Pydantic. The repository describes itself as: Polar — A billing platform for the intelligence era. The licence is MIT.
When your agent uses it
- Asks whether a new helper
- Utility already exists in the codebase
Example prompts
- “/reuse-check”
Workflow steps
3 steps, taken from the first numbered list in SKILL.md.
- Name search — rg -n "def |\b" server/polar clients/packages, plus obvious
- Behaviour search — the distinctive part of the body: a regex literal, a library call
- Inventory — check the list below.
What it can do on your machine
Read from SKILL.md and the folder at commit e4fc909. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
rg
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Reuse Check loads about 1.2k tokens when it runs. Until then it costs about 84 tokens; SKILL.md has 434 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from polarsource/polar at commit e4fc909, republished under its MIT licence (© polarsource). 434 words, ~1,212 tokens.
Download SKILL.mdSave it as
.claude/skills/reuse-check/SKILL.md (or your agent's skills folder).- name
- reuse-check
- description
- Check a diff for code that reinvents something Polar already has — a kit helper, a shared Pydantic type, a repository method, an Orbit component, an existing model property. Use before opening a PR, when reviewing a diff, or when the user asks whether a new helper, validator, type or utility already exists in the codebase.
- license
- MIT
- metadata.author
- polar
- metadata.version
- 1.0.0
Reuse Check (Polar)
The handle is the diff. The evidence is new code that duplicates something the repo already has, with the import that replaces it.
This is the most common substantive comment in Polar reviews: 84 of ~1,100 human review comments from Feb to Aug 2026 point at an existing helper the author did not know about. It is also the one category where grep beats a human reviewer, and it got worse once agents started writing the code, because an agent that does not search first writes its own helper.
Scope
Run on any diff that adds a function, constant, Annotated type, validator, enum, model
property, repository method, React component, or hook. Skip deletions, renames, config and
lockfiles.
Owned elsewhere: agent noise → slop-check; API contract → api-surface-review; deploy
safety → ship-safety; billing behaviour → billing-review.
Method
For each new symbol:
- Name search —
rg -n "def <name>|<Name>\b" server/polar clients/packages, plus obvious synonyms (normalize/sanitize/clean,fetch/get/load). - Behaviour search — the distinctive part of the body: a regex literal, a library call
(
urlparse,pycountry,stdnum,slugify), a magic constant. - Inventory — check the list below.
Report only when you can name the existing symbol and its import path. A hunch is not a finding. Always show what you searched for, so a false positive is cheap to dismiss.
Show full SKILL.md (220 more words)Show less
Inventory
| Home | Holds |
|---|---|
polar/kit/schemas.py | Schema, IDSchema, TimestampedSchema, EmptyStrToNone, SlugValidator, StripValidator, HttpsUrl, HttpUrlToStr, Int32, ClassName, MergeJSONSchema, SetSchemaReference, MultipleQueryFilter, *_ID_EXAMPLE |
polar/kit/http.py | get_safe_return_url (open redirect), get_ip_address, add_query_parameters, get_content_disposition, is_localhost, SSRF-safe crawling (SSRFBlockedError, UnsafeCrawlableUrl, UrlReachability) |
polar/kit/currency.py, money.py, math.py | get_currency_decimal_factor (zero-decimal currencies), get_minimum_currency_amount, get_maximum_currency_amount, format_currency, get_presentment_currency, get_cents_in_dollar_string, polar_round, non_negative_running_sum |
polar/kit/pagination.py | ListResource, Pagination, PaginationParams, count_subquery |
polar/kit/repository/base.py | get_base_statement, get_one_or_none, get_all, paginate, create, update, from_session, stream |
polar/kit/ (rest) | address, anonymization, crypto, csv, db, email (EmailStrDNS), encryption, html, json, jwk, jwt, locale, metadata, operator, routing, services, sorting, time_queries, trial, utils, visibility |
server/scripts/helper.py | run_batched_update |
polar/backoffice/forms.py | Form builder classes. Pattern: polar/backoffice/orders/endpoints.py |
clients/packages/orbit/src/components | Alert, Avatar, Box, Button, ButtonGroup, Checkbox, Grid, GridItem, InlineModal, Input, List, ListGroup, Modal, Pill, SegmentedControl, Select, Spinner, Status, Subnav, Switch, Tabs, Text, TextArea, Tooltip, Truncated, datatable |
| Libraries already in use | stdnum (tax IDs), pycountry (country names), slugify, email_validator |
Also grep the model. A lot of duplicated logic is a property that already exists:
Organization.is_payout_ready, Organization.can_authenticate, ProductPrice.is_free,
Checkout.is_free_product_price, Payment.UNRECOVERABLE_DECLINE_CODES.
The ones people actually miss
- A hand-written "empty string means null" validator instead of
EmptyStrToNone. - A keyset loop over UUIDs instead of
RepositoryBase.stream, which batches implicitly. - Fetching rows only to count them, instead of an existence query.
- Hand-rolled cents conversion or currency rounding.
- A country-code table or slug regex instead of
pycountry/slugify. - A hand-built HTMX form in a new backoffice view.
- A hand-styled div that duplicates an Orbit primitive.
Output
## Reuse
### 🟠 Should fix
- `file:line` — <what the new code does>. Fix: `from polar.kit.schemas import EmptyStrToNone`
(searched: `rg "empty_str|strip_to_none" server/polar`)
### 🟡 Question
- `file:line` — <question>
### Verdict
✅ Nothing reinvented | ❌ n duplicates© polarsource, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in .agents/skills/reuse-check of polarsource/polar.
Open the folder on GitHubat commit e4fc909
Compare with similar skills
Reuse Check next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Reuse Check this skillpolarsource/polar | 10k | — | ~1.2k | Automated safety check: Pass | MIT | |
| Chdb Datastorevemetric/vemetric | 394 | 2 repos | ~1.4k | Automated safety check: Pass | Apache-2.0 | |
| CSV Data Summarizercoffeefuelbump/csv-data-summarizer-claude-skill | 468 | 2 repos | ~1.4k | Automated safety check: Pass | None | |
| Paper FiguresEvoScientist/EvoSkills | 475 | 1 repos | ~4.4k | Automated safety check: Pass | Apache-2.0 | |
| Python Executorcortega26/chile-hub | 113 | 2 repos | ~1.5k | Automated safety check: Pass | MIT | |
| DataframelyQuantco/dataframely | 619 | — | ~2.4k | Automated safety check: Pass | BSD-3-Clause |
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Paper Figures
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Execute Python code in a safe sandboxed environment via [inference.sh](https://inference.sh).
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Related
Works with
Categories
Questions about Reuse Check
What does Reuse Check do?
Check a diff for code that reinvents something Polar already has — a kit helper, a shared Pydantic type, a repository method, an Orbit component, an existing model property. Reuse Check is an agent skill from polarsource/polar. Check a diff for code that reinvents something Polar already has — a kit helper, a shared Pydantic type, a repository method, an Orbit component, an existing model property.
When should I use Reuse Check?
Reuse Check fits situations like: asks whether a new helper; utility already exists in the codebase.
How do I install Reuse Check in Claude Code?
Run `npx skills add polarsource/polar --skill reuse-check -a claude-code`. Or copy the skill folder (.agents/skills/reuse-check in polarsource/polar) into .claude/skills/reuse-check in your project. Claude Code loads it when a task matches its description.
How do I install Reuse Check in Codex?
Run `npx skills add polarsource/polar --skill reuse-check -a codex`. Or copy the skill folder (.agents/skills/reuse-check in polarsource/polar) into .agents/skills/reuse-check in your project. Codex loads it when a task matches its description.
Can I use Reuse Check in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add polarsource/polar --skill reuse-check -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/reuse-check, .gemini/skills/reuse-check, .github/skills/reuse-check and .opencode/skills/reuse-check in your project.
What does Reuse Check need to run?
Going by SKILL.md and its folder, Reuse Check needs the command-line tools its instructions call (rg).
Does Reuse Check access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Reuse Check safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Reuse Check use?
Reuse Check is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Reuse Check use?
About 1.2k tokens (SKILL.md is roughly 4.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Reuse Check?
Skills that share tags, products or a category with Reuse Check: Chdb Datastore (vemetric/vemetric, 394 stars), CSV Data Summarizer (coffeefuelbump/csv-data-summarizer-claude-skill, 468 stars), Paper Figures (EvoScientist/EvoSkills, 475 stars) and Python Executor (cortega26/chile-hub, 113 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Reuse Check?
polarsource (a GitHub organization) maintains it in polarsource/polar, which has 10,340 GitHub stars. The repository holds 18 skills in this directory. The repository was last updated on October 7, 2026.
Source: polarsource/polar on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.