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

# Glossary

> Key terms and concepts used across Morph documentation

## Products

**Fast Apply (Apply)** — File editing model that merges partial code updates into existing files at 10,500 tok/s with 98% accuracy. Uses the `<instruction>/<code>/<update>` message format.

**WarpGrep** — Code search subagent that runs in a separate context window. Explores repositories using built-in tools (`grep_search`, `read`, `list_directory`, `glob`, `finish`). Returns matching code snippets in \~6 seconds.

**Compact (Compactor)** — Context compression model that removes irrelevant lines from chat history and code at 33,000 tok/s. Every surviving line is byte-for-byte identical to the original input.

**Router** — Prompt complexity classifier that returns a model recommendation in \~430ms. Does not generate completions itself. Routes to the optimal model (e.g., `claude-haiku` for simple, `claude-sonnet` for complex).

## Model IDs

| Model         | ID                   | Purpose                                    |
| ------------- | -------------------- | ------------------------------------------ |
| Apply (fast)  | `morph-v3-fast`      | Default file editing, highest speed        |
| Apply (large) | `morph-v3-large`     | Complex edits requiring more reasoning     |
| Apply (auto)  | `auto`               | Router selects fast vs large automatically |
| WarpGrep      | `morph-warp-grep-v1` | Codebase search (local and GitHub)         |
| Compact       | `morph-compactor`    | Context compression                        |
| Embedding     | `morph-embedding-v4` | Code and text embeddings                   |
| Rerank        | `morph-rerank-v4`    | Search result reranking                    |
| Router        | `morph-routers`      | Prompt complexity classification           |

## Message Format Tags

**`<instruction>`** — XML tag in Apply messages describing what the edit does. Including it raises accuracy from 92% to 98%.

**`<code>`** — XML tag containing the original file content to be edited.

**`<update>`** — XML tag containing the partial edit snippet with `// ... existing code ...` markers for unchanged regions.

**`// ... existing code ...`** — Marker placed in `<update>` snippets to indicate regions that should remain unchanged. Required for Apply to correctly merge partial edits.

**`<repo_structure>`** — XML block in WarpGrep messages describing the repository directory layout. Required for local codebase search.

**`<keepContext>`** — XML tag wrapping sections of input that Compact should never remove, regardless of relevance scoring.

## API Concepts

**Base URL** — `https://api.morphllm.com/v1`. All endpoints are OpenAI-compatible and work with any OpenAI SDK.

**Bearer token** — Authentication method for all Morph API endpoints. Obtained from the [dashboard](https://morphllm.com/dashboard/api-keys).

**`query` parameter (Compact)** — Tells Compact what information matters for the next LLM call. Without it, the model infers relevance from the last user message.

**`code_context`** — Parameter in the `edit_file` tool definition containing the original file content to be edited.

**`search_context`** — Parameter in the `codebase_search` tool definition containing the repository structure for WarpGrep queries.