io.github.cyanheads/medical-codes-mcp-server

Decode one or more US medical codes to their official descriptions across ICD-10-CM (diagnoses), ICD-10-PCS (inpatient procedures), HCPCS Level II (supplies/drugs/services), and RxNorm (drugs, by RXCUI). Also decodes a National Drug Code (NDC) directly to its RxNorm product offline, tagged `source: "NDC"` — hyphenated in an FDA segment configuration (4-4-2, 5-3-2, 5-4-1, or the 11-digit 5-4-2) or as bare 10/11 digits; any other segment widths are malformed and stay unresolved. Auto-detects the system from each code\'s shape; pass an explicit `system` only when a value is genuinely ambiguous. Accepts 1–50 codes and returns partial success: resolved codes in `found`, unresolved in `notFound` with a per-code reason, so one bad code never fails the batch. Set `includeHierarchy` to attach each code\'s parent and immediate children (with a `childrenTruncated` flag when a code has more children than the cap returns — walk the full set via medcode_browse_hierarchy or medcode_map_codes). The resolved `system` is echoed on every result for chaining into medcode_map_codes or a billability check; a code string that also exists in another bundled system carries `alsoInSystems` naming it, so a single answer to a colliding code is never mistaken for the only one.

Find US medical codes whose official descriptions match a described concept, via full-text search over the bundled index. Every search term must appear — matched first as a token prefix, then as a substring so inflected and compound forms are also found (a "neuropathy" search surfaces "mononeuropathy"/"polyneuropathy" siblings too, not only a standalone "neuropathy" token). Filter by `system` (ICD10CM/ICD10PCS/HCPCS/RXNORM), `billableOnly` to exclude headers/categories, and `chapter`. Use when you have a clinical description and need the code — the reverse of medcode_get_code. Results echo the resolved system per row for chaining, rank exact prefix matches ahead of substring-only matches with a deterministic tie-break, and disclose truncation with a `nextCursor`: pass it back as `cursor` to page through the full ranked set.

Walk a US medical code system's hierarchy for discovery without a search term. With no `node`, returns the top-level entries (ICD-10-CM categories, HCPCS range buckets, or ICD-10-PCS first-axis values). With a `node`, returns its immediate children. ICD-10-CM and HCPCS use a prefix hierarchy (a shorter code is the parent of a longer one); ICD-10-PCS is axis-based — each of its 7 characters is an independent axis (section, body system, root operation, body part, approach, device, qualifier), but only the top-level Section axis is browsable (omit `node`): positions 2–7 are context-dependent on the preceding axis path and are not enumerable from a flat partial code. Lets an agent orient in an unfamiliar system or enumerate a category's specific codes. A large child set paginates: when the response carries a `nextCursor`, pass it back as `cursor` to fetch the next page.

List the bundled US medical code systems with their release identifiers, effective dates, and code counts. Confirms which ICD-10-CM fiscal year, ICD-10-PCS fiscal year, HCPCS Level II release, and RxNorm normalized set are active before acting on any decode, search, or crosswalk result. The corpus is offline and built at package-build time — this call reports exactly which release is baked into the running server. ICD-10-CM/PCS are the US clinical modifications, not the ICD-10/ICD-11 base.

Crosswalk a US medical code or drug across systems and within a hierarchy. Hierarchy directions: `parents` and `children` walk a code's prefix hierarchy one level per call — immediate parent/children only (depth-1); call iteratively for the full ancestor or descendant path (ICD-10-CM/HCPCS; ICD-10-PCS codes have no prefix parent). A resolvable source with no edge in the requested direction is a successful empty result with a notice, not an error. A source code string that also exists in another bundled system carries `alsoInSystems` naming it, since only the resolved system's hierarchy was walked. Drug directions (RxNorm): `name_to_rxcui` (drug name → RXCUI), `ndc_to_rxcui` and `rxcui_to_ndc` (NDC ↔ RXCUI; NDCs accepted hyphenated in an FDA segment configuration — 4-4-2, 5-3-2, 5-4-1, or the 11-digit 5-4-2 — or as bare 10/11 digits; `ndc_to_rxcui` names the product it decoded to), `rxcui_to_ingredients` and `rxcui_to_brands` (RXCUI → ingredient/brand RXCUIs, each with the target's RxNorm name and its `conceptType` — read that before counting a combination product's ingredients). Every result carries `source` provenance (which system or edge answered) so a chained call (e.g. into openfda with a resolved NDC) uses the right identifier. The `children`, `name_to_rxcui`, and `rxcui_to_ndc` directions can return large sets and paginate: a `nextCursor` in the response is passed back as `cursor` (with an optional `limit` page size) to walk the full set; the point directions ignore both.

Validate whether a US medical code exists, is current, and is billable in the active bundled release. Returns a discriminated status — valid_billable, valid_not_billable, valid_header, or terminated — with a `whyNot` explaining non-billable and terminated cases (e.g. "valid ICD-10-CM category but not billable — submit a more specific child code"). This is the detail a coder needs before submitting a claim. Auto-detects the system from the code\'s shape; pass an explicit `system` to disambiguate. A non-billable or terminated code is a successful result with a whyNot, not an error — only a code that exists in no bundled system raises unknown_code. A code string that also exists in another bundled system carries `alsoInSystems` naming it, since the verdict applies only to the system that answered.