Reference

ctx_prefetch

Input contract and parameters for ctx_prefetch.

Status by featureReviewed September 2026

MCP tool · Planning tools

Call this tool through your MCP client. Its availability depends on your active configuration and profile.

This registry contract is separate from the SDK. For terminal commands, use the CLI reference.

Parameters

Generated from the registered input schema. “Required” reflects the schema; individual actions can impose additional requirements.

budget_tokensinteger

Soft token budget (default: 3000)

changed_filesarray

Changed file paths for computing blast radius

max_filesinteger

Max files to prefetch (default: 10)

rootstring

Project root directory

taskstring

Task description for relevance scoring

Exact JSON schema

Inspect the complete input schema

{
  "properties": {
    "budget_tokens": {
      "description": "Soft token budget (default: 3000)",
      "type": "integer"
    },
    "changed_files": {
      "description": "Changed file paths for computing blast radius",
      "items": {
        "type": "string"
      },
      "type": "array"
    },
    "max_files": {
      "description": "Max files to prefetch (default: 10)",
      "type": "integer"
    },
    "root": {
      "description": "Project root directory",
      "type": "string"
    },
    "task": {
      "description": "Task description for relevance scoring",
      "type": "string"
    }
  },
  "required": [],
  "type": "object"
}

Runtime description

The following is the tool's own agent-facing description, reproduced from the reviewed registry. It can contain implementation terminology; it does not expand the public stability commitment.

Read the agent-facing description

WORKFLOW: call BEFORE context-heavy operations to minimize latency.
ANTIPATTERN: NOT for normal reads — only for proactive cache warming.
Prewarms cache for blast radius files via graph + task signals.
task=description; changed_files=paths for blast radius;
budget_tokens=soft budget (default 3000); max_files=limit (default 10).
Saves latency (not tokens): preloads files before needed.

Sources & versions3 references Reviewed 18 Sept 2026

mcp_manifest.rsrust/src/core/mcp_manifest.rsReviewed checkout
registry.rsrust/src/server/registry.rsReviewed checkout
dynamic_tools.rsrust/src/server/dynamic_tools.rsReviewed checkout

Core checkout: 50fbff09c9
Installed runtime: 3.10.2
SDK release: 1.1.0

Separate baselines for source, CLI/configuration and SDK contracts. Review does not certify every platform or integration.

Versions & compatibility