Web pages into decision-ready state: dates, numbers with units, budgeted chunks. No model, no key.
npx codearia-sieve # MCP server for Claude Code, Cursor and any agent
npm i codearia-sieve # or the library
An agent that needs a web page fetches the whole thing: navigation, cookie banner, footer, ad slots, a megabyte of framework markup. Then a model paid per token digs through the pile for one paragraph.
codearia-sieve does the digging before the model sees anything — and returns the page as state, not prose:
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Dates become dates
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Numbers become facts
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Text becomes chunks that fit Each chunk knows its size in tokens and characters, the blocks it was built from, and the |
Everything else — menus, footers, banners, tag rows, "read more" — is removed, and with trace: true you get the list of what was removed and why.
People who build agents and have seen the bill. Every fetched page costs tens of thousands of tokens before the agent has read a word of it. Median page in the sample: 53 718 tokens in, 1 106 out.
People who run cheap decision models. Classifiers, rankers, System One models like Jev that judge instead of write. They are nearly free and very fast, and they have hard edges: they cannot count, they read dates as text, and their accuracy drops as irrelevant material fills the context. Every "page to markdown" tool prepares input for a reader. This one prepares input for a judge.
People who need answers they can check. A verdict from scraped text is unprovable unless each piece points back to its source. Here every fact names its block and every chunk carries an anchor.
Eight steps of ordinary code. No model runs unless you plug one in. The same HTML gives the same JSON, byte for byte.
robots.txt first; a refusal is reported, not bypassed. Plain HTTP, honest user agent.linkedom. No browser.<head>, bylines and attributes, so both are read before it runs.<span>20 Sept</span><span>10 min</span> never becomes 202610 min.<br><br> become paragraphs too; table rows keep their column headers.state, markdown, usage, warnings, and the trace on request.const r = await sieve({ kind: 'url', url: 'https://docs.typesafe.ai/models' });
r.state.title // "Models"
r.state.facts[0] // { value: 42, unit: "USD_per_billion", label: "price_btok_mtok",
// context: "Price (per Btok / per Mtok) | jev-1.13.0: $42 / $0.042", from: "b3" }
r.state.facts[1] // { value: 0.042, unit: "USD_per_million", … } — paired by position
r.state.chunks[0] // { id: "c1", tokens: 1210, chars: 5357, anchor: "Current models",
// headings: ["Current models", "Pricing", …], blocks: ["b1", …, "b36"], text: "…" }
r.usage // { rawTokens: 127413, stateTokens: 1211,
// visibleChars: 4939, stateChars: 5357, chunks: 1, ms: 1503 }
r.warnings // []
r.markdown // the same article, for a human or a generative model
Expected outcomes never throw. They come back as warnings, each named:
| Warning | Meaning |
|---|---|
robots-disallowed | the site asks crawlers to stay out; we did not fetch |
blocked | a bot challenge or a refusal (403, 405, 429, "Just a moment…"), with the status |
http-error | a 404 or a 500 that still rendered an error page; not the page you asked for |
paywall | the page marks its article as not free; you got the teaser |
empty-without-js | the article container is empty and a script would fill it |
thin-content | a big page that yielded little prose — a front page, a listing |
block-split | one block exceeded the budget and was cut on sentence boundaries |
facts-capped | the page has more facts than the 500 listed — a long fee schedule, say |
You say what you want in plain words. The agent finds the pages, calls sieve_page for each, hands the state to a decision model with a typed question, and writes up the result. Sieve prepares. The judge judges. The agent writes.
{ "mcpServers": { "sieve": { "command": "npx", "args": ["-y", "codearia-sieve"] } } }
Listed in the official MCP Registry as io.github.AntonG87/codearia-sieve; clients that read the registry can install it by name.
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Returns typed |
The text of one chunk from the last result for that URL, no refetch. Overview first, then only what is needed — the tool applies its own idea to itself. |
Pairs with jev-mcp: chunks are sized to fit its fields, so state goes straight into a typed question.
The claim is that a decision model gets better input from Sieve than from raw text. So the output was handed to one. examples/jev.ts drives both MCP servers with the official client — codearia-sieve prepares six pages (API docs, a release note, two Wikipedia articles in two languages, two pricing pages), Jev judges them through jev-mcp. Same run, 21 September 2026:
| Question to Jev | Input from Sieve | Result |
|---|---|---|
jev_classify — what kind of page is this? | title + head of the first chunk, under the tool's 2 000-char limit | 6 of 6 correct; 5 auto, 1 flagged for review — a page that is both docs and a rate card |
jev_verify — is each extracted fact really on the page? | every fact as a claim, its chunks as evidence | 11 of 11 verified, all auto, confidence 0.86–1.0 |
jev_extract — when was it published? | first chunk, a date regex, a description | agrees with Sieve where the page states a date; Sieve also reads JSON-LD and <meta>, which Jev never sees |
The first pass of this test did its job the other way round: Jev sent three facts to review and contradicted one. All four traced to Sieve — a table row labelled by its column header instead of its row header, two rates in one header left unpaired, and a Russian bibliographic "256 с." read as seconds. Fixed, tested, rerun: 11 of 11. A judge that can tell you when your parser is wrong is the point of the whole pairing.
TYPESAFE_API_KEY=… node --experimental-strip-types examples/jev.ts
import { sieve } from 'codearia-sieve';
await sieve({ kind: 'url', url }); // fetch it
await sieve({ kind: 'html', html, url }); // already have it; url only for anchors
await sieve(input, {
budget: { maxTokens: 8000, maxChars: 30000 }, // chunk limits
trace: true, // everything discarded, and why
tokenizer: myTokenizer, // o200k by default; swap for your model's
fetcher: myFetcher, // your transport, or a file reader in tests
now: () => fixedDate, // injected clock: identical output on identical input
selector: mySelector, task: 'is this about pricing?', // relevance judge; nothing runs without one
});
parseDate, findDates and the vendor limits (JEV, JEV_MCP, DEFAULT_BUDGET) are exported too.
thin-content warning, not a fake win.empty-without-js when the container is empty. A site that ships a teaser and streams the rest cannot be told apart without a browser; you get the teaser.examples/pricing-watch.ts.usage.rawTokensEstimated: true.npm install
npm test # 71 tests, offline, a few seconds
npm run demo -- <url> # the token bill for one page
npm run bench # the 20-page benchmark set
npm run analytics # the 56-page random sample: rows, CSV, summary
Design notes — vision and architecture — are in docs/.
Source-derived launch command. Check the maintainer’s required arguments and credentials before running:
npx -y codearia-sieveMerge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.
{
"mcpServers": {
"io-github-antong87-codearia-sieve": {
"command": "npx",
"args": [
"-y",
"codearia-sieve"
]
}
}
}Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.
Claude Desktop setup referenceio.github.AntonG87/codearia-sieve works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.
~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.~/.cursor/mcp.jsonRestart Cursor for changes to take effect..vscode/mcp.jsonReload VS Code window for changes to take effect.~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect..mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.