Valem - Deterministic reactive state models. Create your own calculators/forms with AI
Connect Remote server
claude mcp add --transport http valem https://valem.run/mcp
{
"mcpServers": {
"valem": {
"url": "https://valem.run/mcp"
}
}
}
{
"servers": {
"valem": {
"type": "http",
"url": "https://valem.run/mcp"
}
}
}
Settings > Connectors > Add custom connector
URL: https://valem.run/mcp
Tools 35 found in our last check
list_modelsList the ids of all currently registered Valem models (alphabetical).
create_modelCreate a new model from a declarative ModelSpec. The spec carries the JSON schema plus derivations (computed fields), constraints (invariants), and optional effects. Returns the created id. Fails (isError) on an invalid spec. If the requested id is already taken, a numeric postf…
get_model_infoGet summary info for a model: id, version, and derivation/meta/constraint/effect counts.
get_specGet the full stored ModelSpec JSON for a model.
get_libraryList the JSONata functions and values a model's library exports — what an expression in this model may call, with signature, arity and originating layer. Call it before writing an expression so you reuse the model's existing vocabulary instead of re-deriving it. Returns null whe…
get_stateGet a model's merged state (base fields plus all computed derived fields). On a large model this is the biggest context cost — narrow it: pass 'paths' to project only specific subtrees (canonical addresses, each spliced back into a pruned document at its address), and/or 'depth'…
get_fieldGet the value of a single field by its JSON Path address (e.g. "$.order.total"). Evaluates a LAZY derivation on demand.
mutateApply field mutations to a model and run the reactive pipeline (derivations recompute, constraints enforce, effects dispatch). 'mutations' is a flat map keyed by canonical JSON Path address, e.g. {"$.order.qty": 3}. A ROLLBACK constraint violation returns isError with the struct…
patch_modelApply an RFC 6902 JSON Patch document to a model and run the reactive pipeline. Unlike 'mutate' (a flat address→value map), a patch expresses array insert/remove/move and test/copy ops, e.g. [{"op":"add","path":"/order/items/-","value":{...}}, {"op":"remove","path":"/order/items…
get_effective_schemaGet the effective JSON Schema for a field: the static schema overlaid with LIVE meta-derived constraints (current min/max/required/…). Check this BEFORE writing a value to learn what the reactive pipeline will accept, instead of discovering an invalid mutation only by trying it…
snapshotCapture an immutable point-in-time snapshot of a model's state (base document + derived/meta caches). A natural safety step before a risky evolve_spec: keep the returned snapshot and, if the change goes wrong, hand it back to 'restore' to roll the state back.
restoreRestore a model's state from a snapshot previously returned by 'snapshot' (pass it back verbatim as 'snapshot'). Overwrites the model's current base state. The snapshot must be for the same model.
explainExplain why a field is what it is: returns the recent derivation/constraint trace records for a path from the in-memory ring buffer (inputs, expression, result). For a constraint use the synthetic path "$constraint:<id>". Trace records can be bulky — pass 'limit' to return only…
get_historyList the ISO-8601 timestamps of a model's committed mutations (most recent 100).
get_auditQuery a model's durable, append-only audit trail (newest-first): one record per committed reactive cycle (mutations, derivedUpdated, traces, flaggedConstraints, dispatchedEffects, source, sequence). This is the queryable superset of get_history/explain — it survives the in-memor…
verify_auditVerify the tamper-evidence hash chain of a model's durable audit trail. Returns {valid, recordsChecked, firstBrokenSequence, detail}; a false 'valid' points at the first altered/reordered/deleted record. (Embedded mode has no hash chain and reports valid.)
upload_blobStore binary content (base64-encoded in 'data') in the content-addressed blob store and get back a BlobRef {$blobId, $mediaType, $bytes} to embed in a model's binary field. Storage is content-addressed (SHA-256), so uploading identical bytes returns the same $blobId.
download_blobFetch a blob's bytes by id, base64-encoded in the result. Pass 'modelId' to fetch a blob referenced by a specific model (access-scoped); omit it for a direct store fetch. Large blobs may exceed the result-size limit — this channel suits small binaries only.
evolve_specApply an incremental SpecEvolution diff to a model, preserving live state. Returns the new version. Fails (isError) if the evolved spec is invalid, if expectedVersion no longer matches, or if a schema change would strand existing state. Prefer targeted diffs (upsertSchemaNodes/u…
delete_modelRemove a model from the registry. Fails (isError) if the model does not exist.
get_viewEvaluate a model's embedded view definition against current state and return the resolved component tree. Pass an optional 'viewId' for a named view; omit for the default view.
get_domain_guidanceGet vetted instructions for the hard modelling shapes this domain involves (progressive tax/fee charges, per-period schedules, classification, date math, group-by, …). Read the model description in ANY language, pick the matching topic ids, and call this BEFORE authoring the spe…
validate_specValidate a ModelSpec WITHOUT creating it: returns a 'valid' flag plus structured findings (errors + warnings, each with a location and message). Use this to iterate on a draft — fix the reported errors, re-validate — before committing with create_model.
eval_expressionEvaluate a single JSONata expression against a sample input document and return the computed value, or the exact compile/eval error. Write the expr exactly as in a derivation/constraint 'expr': bare dot-paths, no leading $ (e.g. "loan.amount * loan.annualRate / 1200"). Use this…
test_specRun a spec's embedded test cases (or ad-hoc given->expect cases) through the real reactive pipeline in a throwaway runtime, returning pass/fail plus per-field failures (path, expected, actual). Use this to certify domain behavior before create_model / promotion.
dry_runCompile a candidate ModelSpec in an ISOLATED throwaway runtime, apply optional sample mutations, and return the resulting merged state (base + derived) — WITHOUT registering it in the live registry. Use this to preview the full reactive cascade of a draft spec.
convert_spreadsheetCompile an uploaded .xlsx workbook's OWN formulas into a ready ModelSpec — deterministic transpilation (Excel formula language -> JSONata), never an LLM call: every number the compiled spec computes is checked to exactly match what the source workbook itself computed. One worksh…
search_documentDeterministic, LLM-free search over an uploaded PDF/DOCX: ranks the document's pages/sections against your query (term-overlap, no embedding model, no network call) and returns the top matches with page/section citations and verbatim quotes. Cost is bounded by topK, never by doc…
pair_browserPair this MCP session with a browser tab on the hosted Valem sandbox so both drive the same live model session. Mints a pairing on first call (or resumes an existing not-yet-approved one) and waits up to a minute for the developer to approve it. Returns {status:"paired"|"already…
valem_spec_guideHow to write a Valem ModelSpec that render_model accepts: sections, path notation, JSONata rules, view components and common mistakes. Call this once before writing your first spec in a conversation.
render_modelShow the user a Valem model as an interactive card they can edit in the chat: a form whose computed fields update on every change, checked by a deterministic engine. Use it when the user asks for a calculator, quote, budget, planner, pricing or any model with inputs and computed…
explain_valueExplain how a value in a Valem card was computed: the formula, the values it read and the inputs it ultimately comes from, as Valem's engine has them for the given inputs. Use it when the user asks why a number is what it is. Pass the specHash and current inputs from the latest…
valem_recomputeCalled by the Valem card when the user edits an input. Not for direct use: call render_model instead.
show_modelShow the user one of this server's models (created with create_model) as an interactive card in the chat. Every edit the user makes in the card is a mutate on the model, so get_state and explain see it. Use it after create_model or evolve_spec when the user should see or try the…
valem_card_editCalled by the Valem card when the user edits a stored model. Not for direct use: call mutate instead.
Details
| Endpoint | https://valem.run/mcp (Streamable HTTP) |
| First published | 22 Aug 2026 |
| Last updated | 22 Aug 2026 |
| Registry name | io.github.vlad-public-code/valem |
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