Morph Fast Apply
Fast, AI-powered file editing using the Morph Apply API. Edit files without reading them first. Processes at 10,500 tokens/sec with 98% accuracy.
When to Use
-
Fast file edits without reading entire file first
-
Batch edits to a file (multiple changes in one operation)
-
When you know what to change but file is large
-
Large files where reading would consume too many tokens
Key Pattern: Code Markers
Use // ... existing code ... (or language-appropriate comments) to mark where edits go:
... existing code ...
try: result = process() except Exception as e: log.error(e)
... existing code ...
The API intelligently places your edit in the right location.
Usage
Add error handling
uv run python -m runtime.harness scripts/mcp/morph_apply.py
--file "src/auth.py"
--instruction "Add error handling to login function"
--code_edit "# ... existing code ...
try:
user = authenticate(credentials)
except AuthError as e:
log.error(f'Auth failed: {e}')
raise
... existing code ..."
Add logging
uv run python -m runtime.harness scripts/mcp/morph_apply.py
--file "src/api.py"
--instruction "Add debug logging"
--code_edit "# ... existing code ...
logger.debug(f'Processing request: {request.id}')
... existing code ..."
TypeScript example
uv run python -m runtime.harness scripts/mcp/morph_apply.py
--file "src/types.ts"
--instruction "Add user validation"
--code_edit "// ... existing code ...
if (!user) throw new Error('User not found');
if (!user.isActive) throw new Error('User inactive');
// ... existing code ..."
Parameters
Parameter Description
--file
File path to edit (required)
--instruction
Human description of the change (required)
--code_edit
Code snippet with markers showing where to place edit (required)
vs Claude's Edit Tool
Tool Best For
morph-apply Fast edits, don't need to read file first, large files, batch edits
Claude Edit Small precise edits when file is already in context
Use morph-apply when:
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File is not in context and reading it would be expensive
-
File is very large (>500 lines)
-
Making multiple related edits at once
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You know the context of the change (function name, class, etc.)
Use Claude Edit when:
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File is already in context from prior Read
-
Very precise edits requiring exact old/new string matching
-
Small files (<200 lines)
MCP Server Required
Requires morph server in mcp_config.json with MORPH_API_KEY .
Performance
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Speed: 10,500 tokens/sec
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Accuracy: 98% correct placement
-
Token savings: Don't need to read entire file first