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Python
Remote

storage_rescan

Rescan ESXi host HBAs and VMFS volumes to discover newly presented LUNs and datastores. Returns blast radius preview; apply changes only with explicit confirmation.

Instructions

[WRITE] Rescan all HBAs and VMFS volumes on an ESXi host to discover newly presented LUNs and datastores.

Use this when a storage array presents new LUNs, or after out-of-band SAN changes. Not needed after storage_iscsi_add_target / storage_iscsi_remove_target — those rescan automatically. Without confirm=True this only previews: it returns blast_radius (the host, every adapter the rescan touches, the mounted VMFS volumes) and changes nothing. Show it to the user. Do not set confirm=True on your own because the user asked earlier — they have not seen the preview yet. Deletes nothing, but it is I/O-visible on the host and may take a minute or two with many paths. Refused when the host's storage view cannot be read. Returns a dict.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
targetNoOptional vCenter/ESXi target name from config.
confirmNoFalse (default) returns the blast radius and changes nothing. True applies it.
dry_runNoDeprecated alias for confirm; removed in the next minor release. dry_run=False acts, dry_run=True previews.
host_nameYesESXi host name as shown in vCenter inventory (FQDN or IP). Errors if not found.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed6 schema fields changedv1.11.0
    • addedInput schema / properties / confirm
      Added value: +{
+  "default": false,
+  "description": "False (default) returns the blast radius and changes nothing. True applies it.",
+  "title": "Confirm",
+  "type": "boolean"
+}
    • addedInput schema / properties / dry_run / anyOf
      Added value: +[
+  {
+    "type": "boolean"
+  },
+  {
+    "type": "null"
+  }
+]
    • changedInput schema / properties / dry_run / default
      Previous value: -falseNew value: +null
    • changedInput schema / properties / dry_run / description
      Previous value: -"If true, return a preview of the change without executing it."New value: +"Deprecated alias for confirm; removed in the next minor release. dry_run=False acts, dry_run=True previews."
    • removedInput schema / properties / dry_run / type
      Removed value: -"boolean"
    • changedOutput schema / (root)
      Previous value: -{
-  "properties": {
-    "result": {
-      "title": "Result",
-      "type": "string"
-    }
-  },
-  "required": [
-    "result"
-  ],
-  "title": "storage_rescanOutput",
-  "type": "object"
-}New value: +null
  2. Changed4 schema fields changedv1.8.15
    • addedInput schema / additionalProperties
      Added value: +false
    • addedInput schema / properties / dry_run / description
      Added value: +"If true, return a preview of the change without executing it."
    • addedInput schema / properties / host_name / description
      Added value: +"ESXi host name as shown in vCenter inventory (FQDN or IP). Errors if not found."
    • addedInput schema / properties / target / description
      Added value: +"Optional vCenter/ESXi target name from config."
  3. Changed1 schema field changedv1.6.0
    • addedInput schema / properties / dry_run
      Added value: +{
+  "default": false,
+  "title": "Dry Run",
+  "type": "boolean"
+}
  4. First observedv1.3.2

TDQS

A4.7/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate a non-read, non-idempotent, non-destructive operation, and the description adds important context beyond that: confirm=False previews and returns blast_radius, confirm=True applies changes, the operation is I/O-visible, may take minutes, deletes nothing, and can be refused when the storage view cannot be read. This gives an agent a strong behavioral model.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core purpose and every subsequent sentence earns its place by covering usage timing, preview behavior, safety constraints, side effects, failure conditions, and return type. It is detailed but not bloated.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutating storage operation with no output schema, the description provides the key missing context: the blast_radius result shape, confirmation gating, runtime cost, I/O visibility, and a refusal condition. An agent has enough to invoke it safely and interpret the result.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and every parameter is already documented, including the dry_run deprecation and confirm default behavior. The tool-level description reinforces confirm's gating behavior but does not need to compensate for schema gaps, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Rescan all HBAs and VMFS volumes on an ESXi host to discover newly presented LUNs and datastores.' It clearly defines scope and explicitly distinguishes when related sibling tools are not needed, so an agent can tell it apart from storage_iscsi_add_target and storage_iscsi_remove_target.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description states exactly when to use it ('when a storage array presents new LUNs, or after out-of-band SAN changes') and when not to ('Not needed after storage_iscsi_add_target / storage_iscsi_remove_target — those rescan automatically'). It also gives safety-critical guidance about not setting confirm=True before showing the preview.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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