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

Beyond the annotations (which only declare destructive/not-read-only), the description discloses a rich behavioral contract: slug pre-validation that aborts without consuming one of three backup slots, mandatory security backup with proof-of-existence, and post-update read-back of the actually installed version with explicit honesty about unverifiable outcomes. This is exactly the operational detail an agent needs for a destructive mutation and is not available in the structured fields.

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

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

The critical behavior (single item, slug validation, backup gating, no false success claims) is front-loaded, and each sentence carries operational weight. It is somewhat verbose, restating the honesty guarantee twice ('aktualisiert allein wird nie behauptet' and 'statt Erfolg oder Fehlschlag zu behaupten'), which keeps it from a 5.

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

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

For a destructive, backup-gated mutation with no output schema, the description covers the full lifecycle an agent must anticipate: validation/abort path, backup precondition, update, and version verification result reporting. Nothing essential to calling it correctly is missing.

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

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

Schema description coverage is 100%, so domain, slug, site_url and item_type are already documented in the schema. The description adds only the slug's provenance (get_outdated_plugins) and the one-item-per-call constraint, so the baseline of 3 applies.

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

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

The description states a precise verb+resource+scope: it updates ONE single WordPress plugin or theme, keyed by a slug drawn from get_outdated_plugins. The 'EIN einzelnes' scope plus the plugin/theme distinction clearly separates it from update_wordpress_core and from install/set-state siblings without needing their schemas.

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

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

It gives clear usage context: the slug is sourced from get_outdated_plugins, only one element may be updated per call ('Nie alle auf einmal'), and item_type selects plugin vs theme. It does not explicitly name alternative tools (update_wordpress_core, install_wordpress_plugin) or state when NOT to call it, so it stops short of full when/why-not guidance.

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