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

# Get Definition

> Jump to where a symbol is defined

## Overview

Find where a Python symbol (function, class, variable, etc.) is defined. This provides the "Go to Definition" functionality that lets you navigate to the source code of any symbol.

## Request

<ParamField path="uri" type="string" required>
  File URI (e.g., `file:///workspace/main.py`)
</ParamField>

<ParamField path="line" type="number" required>
  Line number (0-indexed)
</ParamField>

<ParamField path="character" type="number" required>
  Character position (0-indexed)
</ParamField>

## Response

<ResponseField name="locations" type="array">
  Array of definition locations (usually just one)

  <Expandable title="Location Object">
    <ResponseField name="uri" type="string">
      File URI where symbol is defined
    </ResponseField>

    <ResponseField name="range" type="object">
      Text range of the definition

      <Expandable title="Range">
        <ResponseField name="start" type="object">
          Start position (`line`, `character`)
        </ResponseField>

        <ResponseField name="end" type="object">
          End position (`line`, `character`)
        </ResponseField>
      </Expandable>
    </ResponseField>
  </Expandable>
</ResponseField>

## Example Request

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://api.pylancemcp.dev/v1/tools/call \
    -H "Authorization: Bearer YOUR_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "name": "get_definition",
      "arguments": {
        "uri": "file:///workspace/app/views.py",
        "line": 42,
        "character": 15
      }
    }'
  ```

  ```python Python theme={null}
  from pylance_mcp import Client

  client = Client(api_key="YOUR_API_KEY")

  definitions = client.get_definition(
      uri="file:///workspace/app/views.py",
      line=42,
      character=15
  )

  for location in definitions.locations:
      print(f"Defined at: {location.uri}")
      print(f"Line: {location.range.start.line}")
  ```

  ```javascript JavaScript theme={null}
  import { PylanceMCP } from '@pylance-mcp/client';

  const client = new PylanceMCP({ apiKey: 'YOUR_API_KEY' });

  const definitions = await client.getDefinition({
    uri: 'file:///workspace/app/views.py',
    line: 42,
    character: 15
  });

  definitions.locations.forEach(location => {
    console.log(`Defined at: ${location.uri}`);
    console.log(`Line: ${location.range.start.line}`);
  });
  ```

  ```typescript TypeScript theme={null}
  import { PylanceMCP, DefinitionRequest } from '@pylance-mcp/client';

  const client = new PylanceMCP({ apiKey: process.env.PYLANCE_API_KEY! });

  const request: DefinitionRequest = {
    uri: 'file:///workspace/app/views.py',
    line: 42,
    character: 15
  };

  const definitions = await client.getDefinition(request);

  for (const location of definitions.locations) {
    console.log(`Defined at: ${location.uri}`);
    console.log(`Line: ${location.range.start.line}`);
  }
  ```
</CodeGroup>

## Example Response

```json theme={null}
{
  "locations": [
    {
      "uri": "file:///workspace/app/models.py",
      "range": {
        "start": { "line": 15, "character": 6 },
        "end": { "line": 15, "character": 10 }
      }
    }
  ]
}
```

## Use Cases

### Navigate to Function Definition

```python theme={null}
# In views.py, line 42:
result = calculate_total(items)
#        ^^^^^^^^^^^^^^
# Get definition → Goes to utils.py where calculate_total is defined

# Result:
# file:///workspace/app/utils.py, line 8
# def calculate_total(items: List[Item]) -> float:
```

### Find Class Definition

```python theme={null}
# In views.py:
user = User(name="John", email="john@example.com")
#      ^^^^
# Get definition → Goes to models.py

# Result:
# file:///workspace/app/models.py, line 25
# class User(BaseModel):
```

### Jump to Import Source

```python theme={null}
# In views.py:
from app.utils import calculate_total
#                     ^^^^^^^^^^^^^^
# Get definition → Goes to utils.py

# Result:
# file:///workspace/app/utils.py, line 8
```

### Find Variable Declaration

```python theme={null}
# In functions.py:
total = calculate_total(items)
# ... many lines later ...
print(total)  # Where was total defined?
#     ^^^^^
# Get definition → Goes back to where total was assigned
```

## Multiple Definitions

Some symbols may have multiple definitions (e.g., overloaded functions, re-exports):

```json theme={null}
{
  "locations": [
    {
      "uri": "file:///workspace/app/models.py",
      "range": { "start": { "line": 15, "character": 6 }, "end": { "line": 15, "character": 10 } }
    },
    {
      "uri": "file:///workspace/app/__init__.py",
      "range": { "start": { "line": 3, "character": 0 }, "end": { "line": 3, "character": 23 } }
    }
  ]
}
```

<Info>
  When multiple definitions exist, the first one is typically the primary definition.
</Info>

## Definition Types

| Symbol Type  | What You Get                                  |
| ------------ | --------------------------------------------- |
| **Function** | The `def` statement where function is defined |
| **Class**    | The `class` statement where class is defined  |
| **Variable** | The line where variable is first assigned     |
| **Import**   | The source file of the imported module/symbol |
| **Method**   | The method definition inside the class        |
| **Property** | The `@property` decorated method              |

## Performance Tips

<Tip>
  **Cache Definition Locations**: Store frequently accessed definitions to reduce lookups
</Tip>

<Tip>
  **Batch Requests**: If checking multiple symbols, batch them in one request
</Tip>

<Tip>
  **Workspace Indexing**: Initial workspace load may take time; subsequent lookups are fast
</Tip>

## Error Responses

| Code                   | Reason                             | Solution                            |
| ---------------------- | ---------------------------------- | ----------------------------------- |
| `FILE_NOT_FOUND`       | File doesn't exist                 | Verify file path                    |
| `INVALID_POSITION`     | Position out of bounds             | Check line/character values         |
| `NO_DEFINITION_FOUND`  | No symbol at position              | Move cursor to a valid symbol       |
| `EXTERNAL_DEFINITION`  | Symbol defined in external library | Not available for external packages |
| `WORKSPACE_NOT_LOADED` | Workspace still indexing           | Wait and retry                      |

## Rate Limits

| Tier           | Requests/Hour | Requests/Day |
| -------------- | ------------- | ------------ |
| **Free**       | 20            | 100          |
| **Hobby**      | 500           | 5,000        |
| **Pro**        | 5,000         | 50,000       |
| **Enterprise** | Unlimited     | Unlimited    |

## Related Tools

<CardGroup cols={2}>
  <Card title="Get References" icon="link" href="/api-reference/tools/get-references">
    Find all places where a symbol is used
  </Card>

  <Card title="Get Hover" icon="info-circle" href="/api-reference/tools/get-hover">
    See documentation without jumping
  </Card>

  <Card title="Get Type Definition" icon="t" href="/api-reference/tools/get-type-definition">
    Go to type definition instead of value
  </Card>

  <Card title="Rename Symbol" icon="pen" href="/api-reference/tools/rename-symbol">
    Rename symbol across entire project
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</CardGroup>