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FIDE Laws of Chess

by arxo.io · remote · local (npm) · no sign-in to list tools · v0.1.1 · published by io.arxo

FIDE Laws of Chess (2023) as an executable model: arbiter cases, answers with rules and judgments

Deletes · 1Final · 2Changes · 9

16 tools: 1 can delete or cancel things, 2 do something that can't be undone, 9 change things and 4 only read.

Scanned Oct 21, 2026

4 checks matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http fide-chess https://mcp.arxo.io/mcp/fide-chess

Findings

Matches of fixed checks, with the text they matched.

2 warn2 info
  • The server marks "law_capture_answer" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":false,"openWorldHint":false}; The name "law_capture_answer" says "capture": a word that usually means money moves, which cannot be taken back.

    What this check looks for
  • The server marks "law_ask" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":false,"openWorldHint":false}; The description's first verb is "put": a word for a change.

    What this check looks for
  • The description is 2,130 characters long, over the 2,000 this check looks for.

    Matched text

    description ends: "...preview of these lists and names the count and the ready-made call for the mode."

    What this check looks for
  • The description is 2,029 characters long, over the 2,000 this check looks for.

    Matched text

    description ends: "...cution (QUERY_TOO_BROAD), a continuation on another snapshot as SNAPSHOT_CHANGED."

    What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

16 tools

Deletes or cancels 1Claude Code: deny
  • law_revoke_answerRevoke a published document using its separate secret.No findings

    Why it is in this group

    • The name "law_revoke_answer" says "revoke": a word for removing or ending something.
    • The server marks it destructive (destructiveHint: true).
    Description, as the server wrote it
    Revoke a published document using its separate secret. The public id alone grants no control; revocation closes the HTML page, the API and the download.

    Annotations the server declares

    • destructiveHint: true
    • idempotentHint: true
    • openWorldHint: true
    • readOnlyHint: false
    • title: Revoke a write-up
Can't be undone 2Claude Code: ask
  • law_capture_answerRun a registered producer and obtain producerControl/0.2 for a later verifiable preparation of a Lens.1 finding

    Why it is in this group

    • The name "law_capture_answer" says "capture": a word that usually means money moves, which cannot be taken back.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "law_capture_answer" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":false,"openWorldHint":false}; The name "law_capture_answer" says "capture": a word that usually means money moves, which cannot be taken back.

      What this check looks for
    Description, as the server wrote it
    Run a registered producer and obtain producerControl/0.2 for a later verifiable preparation of a Lens. The producer is chosen only from the shipped registry.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Capture a result for a Lens
  • law_publish_answerPublish a prepared document.No findings

    Why it is in this group

    • The name "law_publish_answer" says "publish": a word for a change that another call does not undo.
    Description, as the server wrote it
    Publish a prepared document. Repeating it with the same preparationId idempotently returns the same URL and the same separate revocation secret.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: true
    • readOnlyHint: false
    • title: Publish a write-up
Changes things 9Claude Code: ask
  • law_answer_capabilitiesA machine-readable matrix of the Lens producers that are actually installed, of replay/projection checks, profiles, limits and the contract tests that confirm them.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    A machine-readable matrix of the Lens producers that are actually installed, of replay/projection checks, profiles, limits and the contract tests that confirm them. declared_only means a schema with no executable witness.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Lens capabilities
  • law_askPut a question to formalised law.1 finding

    Why it is in this group

    • The description's first verb is "put": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "law_ask" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":false,"openWorldHint":false}; The description's first verb is "put": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Put a question to formalised law. When the answer is "not established" it carries whyNot — the engine's why_not report: the candidate rules and the state of every conjunct (satisfied / not satisfied / undetermined); the missing facts are visible there and need not be guessed. BEFORE THE FIRST call obtain the predicate names through law_search (a question in your own words → addresses) or law_packages (the signatures of a known instrument) — an invented name will be rejected. If the tool returned an error or "not established", THAT IS THE ANSWER: pass it to the user and do not substitute general knowledge about the law of some other country. But "I found no suitable instrument" is NOT an answer until law_search has been asked: silence of the catalogue is a property of searching by title, not a conclusion about the corpus. kind='truth' — whether a fact is established; kind='collect' — enumerate the records; kind='deadline' — compute a time limit on the official calendar; kind='positions' — which DUTIES arose from the facts and what their statuses are; kind='why_not' — the why_not report on the same goal, whatever the status of the answer. The answer carries the rules applied, the warnings and the provenance with hashes; truth/collect also carry a signature block for presentation. The server does not guess: where a norm is not formalised, the answer is "not established" or an error.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Ask the law
  • law_case_askThe ask operation: run a registered case of a case package over its pinned dependencies and return the answer: by default a projection of the evaluation document without the proof …No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    The ask operation: run a registered case of a case package over its pinned dependencies and return the answer: by default a projection of the evaluation document without the proof graph, on responseMode full or proof: true the canonical document with a proof and a manifest. The question is JSON per query.schema.json (query), an evaluate string (evaluate + queryId), a saved queryId without query, or card + args. A refusal to prepare is an error with an LDC-* code, never an empty answer.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Case package: ask
  • law_packagesThe catalogue of formalised law: instruments, predicates with signatures, the boundaries of coverage.1 finding

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Info

      The description is 2,130 characters long, over the 2,000 this check looks for.

      Matched text

      description ends: "...preview of these lists and names the count and the ready-made call for the mode."

      What this check looks for
    Description, as the server wrote it
    The catalogue of formalised law: instruments, predicates with signatures, the boundaries of coverage. This is where the NAMES of predicates come from — they must never be guessed. But do NOT start from the catalogue when looking for the right instrument: the overview is large, and the title of an instrument rarely matches the words of a question ("Newton's laws of motion" contains no word "physics"). A question in your own words goes to law_search first, which returns addresses; the catalogue is for the exact signature of what you found. With no arguments — the overview: one line per instrument (key, title, legal order, counters of rules, facts, signatures, norms, constants); a whole instrument — package="kz-gpk"; a search over the signatures, labels and constants of every instrument — query="substring". All three modes are PAGED: limit and offset, with the remainder named in the text (`showing a–b of N; k more`) and in structuredContent (total, truncated, next — a ready-made continuation call). The unit of a page is named by pageUnit: the overview and query page over INSTRUMENTS (20 and 20 by default), package=… pages over the SIGNATURES of one instrument (20 by default, 300 at most) — large codes carry thousands. package=… together with catalog=… pages a separate list of the instrument: "questions" — the CATALOGUE OF QUESTIONS: which enquiries are provided for (a question in words, a form, a predicate or norms) and what the instrument does NOT answer, with the type of reason; a card is a template of an enquiry, not an answer, and not every instrument has one; "norms" — the NORMS of the instrument, "constants" — the CONSTANTS (names of declarations). "task-guides" — TASK GUIDES: the order of applying a canon to a document — what to gather, which cards to ask and how to read the answers; a guide answers nothing. catalog="task-guides" is allowed without package too — every guide of the profile; guide=… — the detail of one guide; the walkthrough — MCP Prompts under the same name. The detail of an instrument prints a preview of these lists and names the count and the ready-made call for the mode.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Catalogue of law
  • law_passportPassport of an exact release: purpose, interface, boundaries, checks and performance.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Passport of an exact release: purpose, interface, boundaries, checks and performance. The reports section holds the history of measurements, failures included. Entries are paged by JSON Pointer; next continues the answer.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Release passport
  • law_prepare_answerAt the explicit request of the user, repeat between 1 and 12 earlier law_ask or law_process_run calls, compare their replayControl strictly, and prepare a non-public frozen documen…No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    Description, as the server wrote it
    At the explicit request of the user, repeat between 1 and 12 earlier law_ask or law_process_run calls, compare their replayControl strictly, and prepare a non-public frozen document for 24 hours. The client never supplies the machine answer: the server obtains it only by executing afresh. A divergence in any input, in the law, in a resource, in the server code, in the engine library or in the result rejects the document as a whole.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: false
    • title: Prepare a public write-up
  • law_rulesThe rules of formalised law put into words: exactly how a predicate is derived (premises, source articles).No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    The rules of formalised law put into words: exactly how a predicate is derived (premises, source articles). Call this BEFORE supplying facts to law_ask — the rules say which facts are needed instead of leaving them to be guessed. For large instruments package=… returns a table of contents; the full text comes from predicate=…. The listing by package is paged: limit (20 by default, 500 at most) and offset; the remainder is named in the text (`showing a–b of N; k more`) and in structuredContent (total, truncated, next — a ready-made continuation call).

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Rules of inference
  • law_screenBuild a necessary condition — a superset — for the preliminary selection of rows from an external source.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Build a necessary condition — a superset — for the preliminary selection of rows from an external source. This is NOT a legal answer and NOT SQL: the result is a typed tree and a manifest of the extensions up to TRUE. Every row that passes must then be computed in full by the engine, with a proof graph, on the same snapshot of the data. The binding is passed as a pinnable object; sourceSchemaContentHash is the actual hash of the source schema and is compared loudly with the pin. Case facts that carry provenance (origin, document, quote, extractor) are supplied to law_ask, not here. The confidence figure is read by the package EvidencePolicy, not by this tool and not by the engine.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Population screening
  • law_sourcesSources: by default short excerpts (view=summary), 5 texts per page, with the address of the full text in fragments[].full.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Sources: by default short excerpts (view=summary), 5 texts per page, with the address of the full text in fragments[].full. Either package or fragment is required (a StableId from law_search/law_rules). view=full returns exact parts of the text: textRange sets a range of Unicode characters, fragments[].next is the continuation with a contentHash. The hash refers to the WHOLE source, not to the excerpt or the part. textOffset/textLimit require fragment; a continuation requires contentHash. Lists are paged with offset/limit; the answer budget may shrink a page.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Official text
Only reads 4Claude Code: allow
  • law_explainUnfold the proof of a law_ask answer into a chain "rule ← premises → conclusion".No findings

    Why it is in this group

    • The name "law_explain" says "explain": a word for reading.
    Description, as the server wrote it
    Unfold the proof of a law_ask answer into a chain "rule ← premises → conclusion". The compact input: question (the original law_ask arguments, truth/collect), resultHash and codeHash from the provenance of the answer. The server repeats the computation and compares the hashes; if anything changed it refuses explicitly. Alternatively pass the evaluation from law_ask(proof=true). answerResource=fullAnswer.uri explains a stored compact snapshot without recomputing and without the client loading pages; by default only the proofRef chain. nodeId selects one node and all of its premises (up to 24 KB, otherwise an explicit refusal). proofHash refers to the whole graph; scope marks the part selected.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: Unfold the proof
  • law_inspectEvaluation inspector over a SAVED evaluation document: summary — the origin card, resultHash and snapshot verification, listings of results, positions and issues; slice — the closu…No findings

    Why it is in this group

    • The name "law_inspect" says "inspect": a word for reading.
    Description, as the server wrote it
    Evaluation inspector over a SAVED evaluation document: summary — the origin card, resultHash and snapshot verification, listings of results, positions and issues; slice — the closure of proof nodes for a query, rule, position or node with addresses, both sides of BOTH, defeats, values, names resolved against the snapshot; diff — what changed between two documents on the context, result and justification levels; locate — the declaration by StableId. Nothing is evaluated or recomputed: the source is evaluation from law_ask(proof=true) or an answerResource. Missing data is a limit state (limits), never a negation.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
    • readOnlyHint: true
    • title: Evaluation inspector
  • law_queryA deterministic LawQL query over the CLIR of a formalization: a question about the model of the act itself, not about a case.1 finding

    Why it is in this group

    • The name "law_query" says "query": a word for reading.

    Findings

    • Info

      The description is 2,029 characters long, over the 2,000 this check looks for.

      Matched text

      description ends: "...cution (QUERY_TOO_BROAD), a continuation on another snapshot as SNAPSHOT_CHANGED."

      What this check looks for
    Description, as the server wrote it
    A deterministic LawQL query over the CLIR of a formalization: a question about the model of the act itself, not about a case. Relations (14): anchors, edges, fields, imports, interpretations, labels, links, literals, nodes, norms, positions, rules, variables, windows. Full field lists: `law query --schema`. Functions (9): anchor/1, labels/1..2, short/1, contains/2, overlaps/2, starts_with/2, ends_with/2, position/2, derivation/2. exists/not exists over a bound variable; equality and membership only, no arithmetic and no ordering comparisons. Scope: corpus by package.name (for example kz.corpus.labour_code, not a file name) or a glob; without corpus, the whole profile slice; a scope outside the profile is empty (CORPUS_EMPTY). Examples: `from r in rules where r.head_predicate == "urn:…#eligible" select r.id as producer, r.strength as strength, anchor(r.id) as anchors` — who produces; `from l in literals where l.predicate == "urn:…#eligible" select l.node as reader, l.context as context` — who reads; `query eligible over "pkg" { for x: Person; where applicant(x); select eligible(x); }` — inference by the core. This is orchestration over the CLIR and the core; no new legal semantics is implemented here. Instead of text, a question from the catalog with arguments: anchors-of, imports-of, links-of, producers, readers, type-step (see `law query --list` for the set) (predicate/node/type parameters are URNs, pkg is a package.name or a glob). A structural answer is a queryPage: resultHash of the full queryResult, snapshot (hash of the scope package list), rowCount, rows by rowLimit (20, at most 5000) and rowOffset, next with the snapshot for continuation; full: true returns the full queryResult when the scope is one package. Every row carries provenance (CLIR nodes); an empty answer carries the explain funnel (emptyAt names the clause); errors carry LDC-Qxxxx codes with hints; a source product too wide is refused before execution (QUERY_TOO_BROAD), a continuation on another snapshot as SNAPSHOT_CHANGED.

    Annotations the server declares

    • destructiveHint: false
    • idempotentHint: false
    • openWorldHint: false
    • readOnlyHint: true
    • title: LawQL query

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 0.1.1. Values in angle brackets are yours to fill in.

claude mcp add --transport http fide-chess https://mcp.arxo.io/mcp/fide-chess

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__fide-chess__law_search",
      "mcp__fide-chess__law_explain",
      "mcp__fide-chess__law_inspect",
      "mcp__fide-chess__law_query"
    ],
    "ask": [
      "mcp__fide-chess__law_passport",
      "mcp__fide-chess__law_answer_capabilities",
      "mcp__fide-chess__law_capture_answer",
      "mcp__fide-chess__law_prepare_answer",
      "mcp__fide-chess__law_publish_answer",
      "mcp__fide-chess__law_packages",
      "mcp__fide-chess__law_ask",
      "mcp__fide-chess__law_screen",
      "mcp__fide-chess__law_rules",
      "mcp__fide-chess__law_case_ask",
      "mcp__fide-chess__law_sources"
    ],
    "deny": [
      "mcp__fide-chess__law_revoke_answer"
    ]
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as fide-chess. Review it before you use it.