> ## Documentation Index
> Fetch the complete documentation index at: https://docs.corti.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Medical Coding

> Assign medical diagnosis and procedure codes from clinical notes using AI-assisted coding

```json theme={null}
[
  {
    name: "coding-expert",
    type: "reference",
  }
]
```

The **Medical Coding** expert assigns diagnosis and procedure codes from clinical text using a structured, AI-assisted workflow. It can identify codes relevant to an admission even from incomplete data, and selects the most appropriate code system at runtime.

<Tip>
  Medical Coding is essential for billing, claims, CDI, and revenue-cycle workflows where accurate, guideline-compliant codes are required.
</Tip>

## Capabilities

The Medical Coding expert can:

* Predict candidate codes from a full clinical note
* Search a code system from clinical text fragments
* Explore the structure of a code system to drill into candidate codes
* Retrieve coding guidelines that govern a given code or scenario
* Verify a final code sequence against the code system before returning it

## Workflows

Every code assignment follows one of the structured workflows below. `explore()`, `guidelines()`, and `verify()` are always called — they are never skipped.

* **SEARCH-FIRST** (from clinical text): `search()` → `explore()` → `guidelines()` → `verify()`
* **PREDICT-FIRST** (from a full clinical note): `predict()` → `explore()` → `guidelines()` → `verify()`
* **GUIDELINES-FIRST** (unfamiliar conventions): `guidelines()` → `search()` → `explore()` → `guidelines()` → `verify()`
* **VERIFY-AND-NARROW** (refine predictions): `predict()` → `explore()` + `guidelines()` → `verify()` → `predict(filter=include/exclude)` → `verify()`
* **EXPLORE-FIRST** (browse code system): `explore()` → `explore()` drill down → `guidelines()` → `verify()`

The expert never relies on `search()` alone — it can return overly specific codes or miss applicable coding rules. Codes already present in the orchestrator's `tool_data_part` are preferred; MCP tools are only invoked if suitable codes are absent or insufficient.

## Use cases

* Automated coding for billing and claims
* Clinical documentation improvement (CDI) and audit support
* Code validation and verification against guidelines
* Revenue-cycle management

## Detailed information

The Medical Coding expert is wired to a coding MCP server with an extended call timeout to accommodate prediction and verification workflows. The general `coding-expert` calls `list_code_systems()` first and selects from any supported code system at runtime.

For details on the supported code systems and use cases, see the [Medical Coding tab](/coding/overview).

## Code-system-specific variants

In addition to the general `coding-expert`, the registry exposes pre-configured variants that lock the expert to a single code system. Use these when you know which system you want to code in and don't need the expert to discover code systems at runtime.

| Key                        | Code system                                                                               |
| -------------------------- | ----------------------------------------------------------------------------------------- |
| `coding-expert-icd-10-cm`  | ICD-10-CM — US diagnosis coding                                                           |
| `coding-expert-icd-10-int` | ICD-10 WHO — international diagnosis coding (uses `icd-10-who` for search/explore/verify) |
| `coding-expert-icd-10-pcs` | ICD-10-PCS — US inpatient procedure coding                                                |
| `coding-expert-icd-10-uk`  | ICD-10-UK — UK diagnosis coding                                                           |

Each variant shares the same workflows and capabilities documented above.