Ctxo

## ctxo MCP Tool Usage (MANDATORY)

**ALWAYS use ctxo MCP tools before reading source files or making code changes.** The ctxo index contains dependency graphs, git intent, anti-patterns, and change health that cannot be derived from reading files alone. Skipping these tools leads to blind edits and broken dependencies.

### Before ANY Code Modification
1. Call `get_blast_radius` for the symbol you are about to change — understand what breaks
2. Call `get_why_context` for the same symbol — check for revert history or anti-patterns
3. Only then read and edit source files

### Before Starting a Task
| Task Type | REQUIRED First Call |
|---|---|
| Fixing a bug | `get_context_for_task(taskType: "fix")` |
| Adding/extending a feature | `get_context_for_task(taskType: "extend")` |
| Refactoring | `get_context_for_task(taskType: "refactor")` |
| Understanding code | `get_context_for_task(taskType: "understand")` |

### Before Reviewing a PR or Diff
- Call `get_pr_impact` — single call gives full risk assessment with co-change analysis

### When Exploring or Searching Code
- Use `search_symbols` for name/regex lookup — DO NOT grep source files for symbol discovery
- Use `get_ranked_context` for natural language queries — DO NOT manually browse directories

### Orientation in Unfamiliar Areas
- Call `get_architectural_overlay` to understand layer boundaries
- Call `get_symbol_importance` to identify critical symbols

### NEVER Do These
- NEVER edit a function without first calling `get_blast_radius` on it
- NEVER skip `get_why_context` — reverted code and anti-patterns are invisible without it
- NEVER grep source files to find symbols when `search_symbols` exists
- NEVER manually trace imports when `find_importers` gives the full reverse dependency graph