> ## Documentation Index
> Fetch the complete documentation index at: https://gofastmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.
# code_mode
# `fastmcp.experimental.transforms.code_mode`
## Classes
### `SandboxProvider`
Interface for executing LLM-generated Python code in a sandbox.
WARNING: The `code` parameter passed to `run` contains untrusted,
LLM-generated Python. Implementations MUST execute it in an isolated
sandbox — never with plain `exec()`. Use `MontySandboxProvider`
(backed by `pydantic-monty`) for production workloads.
**Methods:**
#### `run`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
run(self, code: str) -> Any
```
### `MontySandboxProvider`
Sandbox provider backed by `pydantic-monty`.
**Args:**
* `limits`: Resource limits for sandbox execution. Supported keys:
`max_duration_secs` (float), `max_allocations` (int),
`max_memory` (int), `max_recursion_depth` (int),
`gc_interval` (int). All are optional; omit a key to
leave that limit uncapped.
**Methods:**
#### `run`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
run(self, code: str) -> Any
```
### `Search`
Discovery tool factory that searches the catalog by query.
**Args:**
* `search_fn`: Async callable `(tools, query) -> matching_tools`.
Defaults to BM25 ranking.
* `name`: Name of the synthetic tool exposed to the LLM.
* `default_detail`: Default detail level for search results.
`"brief"` returns tool names and descriptions only.
`"detailed"` returns compact markdown with parameter schemas.
`"full"` returns complete JSON tool definitions.
* `default_limit`: Maximum number of results to return.
The LLM can override this per call. `None` means no limit.
### `GetSchemas`
Discovery tool factory that returns schemas for tools by name.
**Args:**
* `name`: Name of the synthetic tool exposed to the LLM.
* `default_detail`: Default detail level for schema results.
`"brief"` returns tool names and descriptions only.
`"detailed"` renders compact markdown with parameter names,
types, and required markers.
`"full"` returns the complete JSON schema.
### `GetTags`
Discovery tool factory that lists tool tags from the catalog.
Reads `tool.tags` from the catalog and groups tools by tag. Tools
without tags appear under `"untagged"`.
**Args:**
* `name`: Name of the synthetic tool exposed to the LLM.
* `default_detail`: Default detail level.
`"brief"` returns tag names with tool counts.
`"full"` lists all tools under each tag.
### `ListTools`
Discovery tool factory that lists all tools in the catalog.
**Args:**
* `name`: Name of the synthetic tool exposed to the LLM.
* `default_detail`: Default detail level.
`"brief"` returns tool names and one-line descriptions.
`"detailed"` returns compact markdown with parameter schemas.
`"full"` returns the complete JSON schema.
### `CodeMode`
Transform that collapses all tools into discovery + execute meta-tools.
Discovery tools are composable via the `discovery_tools` parameter.
Each is a callable that receives catalog access and returns a `Tool`.
By default, `Search` and `GetSchemas` are included for
progressive disclosure: search finds candidates, get\_schema retrieves
parameter details, and execute runs code.
The `execute` tool is always present and provides a sandboxed Python
environment with `call_tool(name, params)` in scope.
**Methods:**
#### `transform_tools`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
transform_tools(self, tools: Sequence[Tool]) -> Sequence[Tool]
```
#### `get_tool`
```python theme={"theme":{"light":"snazzy-light","dark":"dark-plus"}}
get_tool(self, name: str, call_next: GetToolNext) -> Tool | None
```