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ha-nexus-agent

by Fistacho
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Python
Local

Update an add-on

supervisor_update_addon
Destructive

Applies an available Home Assistant add-on update when update_available is true by downloading and installing the new version; restore a backup to revert.

Instructions

Update an add-on to its latest available version.

Calls POST /addons/<slug>/update, which downloads and installs the new version over the network; the previous version is only recoverable from a backup taken beforehand.

Use when: update_available is true for the add-on and the new version should be applied. Not for: reverting an update — restore a backup via supervisor_restore_backup instead; there is no dedicated rollback call. Returns: Supervisor's update-job result. Errors: {"error": "invalid_slug"} for a bad slug; {"error": "SUPERVISOR_TOKEN not set — Nexus must run as HA add-on for Supervisor API"} when the token env var is missing; {"error": "HTTP <status>", "detail": ...} on a failed update. Limits: downloads the new version over the network; no automatic rollback on failure.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
slugYesAdd-on slug to update, e.g. from `supervisor_list_addons`.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changedv0.25.1
    • addedInput schema / properties / slug / description
      Added value: +"Add-on slug to update, e.g. from `supervisor_list_addons`."
  2. First observedv0.3.0

TDQS

A4.6/5.0
Behavior5/5

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

Annotations already flag destructiveHint=true, openWorldHint=true and non-idempotent, and the description meaningfully extends them: network download, previous version only recoverable from a prior backup, no automatic rollback on failure, plus concrete error shapes and the missing-token failure mode.

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

Conciseness4/5

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

Front-loaded purpose followed by labelled blocks (Use when / Not for / Returns / Errors / Limits) makes it scannable. It is on the longer side, but each block carries non-redundant operational information.

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 destructive, network-touching Supervisor mutation, the definition covers trigger, exclusions, reversibility, failure modes and even the API route; the output schema already handles return values, so nothing material is missing.

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?

Only one parameter and schema coverage is 100%, so the schema fully documents slug, including its source (supervisor_list_addons). The description adds no syntax or format detail beyond that, so the baseline of 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?

States a specific verb+resource ('Update an add-on to its latest available version') plus the underlying endpoint POST /addons/<slug>/update. Clearly distinct from supervisor_install_addon, supervisor_uninstall_addon and hacs_update_hacs_repository.

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?

Explicit 'Use when: update_available is true' trigger, and an explicit 'Not for' with the correct alternative (supervisor_restore_backup) for reverting, noting there is no rollback call. Nothing left to inference.

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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