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

Far exceeds what annotations convey: it discloses that confirm=false previews the change, that adding a language twice is safe and reports the existing one, that WPML cannot add languages, and that an unregistered language makes wordpress_create_post silently fall back to default. The destructive/structural nature aligns with destructiveHint=true.

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?

Front-loads the two modes and then the high-stakes failure mode before the parameter details, so every sentence carries operational value. It is dense and long for a single paragraph, but there is little outright filler.

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 9-parameter, multi-mode, structural-change tool the description covers the workflow, the silent-failure trap, provider limitations, idempotency behavior and preview semantics. Return values need not be described since an output schema exists.

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?

With 0% schema coverage the description must carry the parameter burden, and it explains the critical ones well: action default, code semantics (the string later passed to wordpress_create_post), locale derivation from code, automatic rtl for Arabic/Hebrew/Persian/Urdu, and confirm as a preview toggle. It leaves flag, name, order and site_url undocumented, so coverage is strong but not complete.

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?

States a specific verb+resource for both modes: lists the languages a multilingual WordPress site (Polylang/WPML) is configured for and adds a new one, with 'list' as the default action. It is immediately distinguishable from siblings like wordpress_link_translations and wordpress_create_post, which it explicitly names.

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?

Gives explicit when-to-use guidance and exclusions: add is the FIRST step of publishing in another language, and skipping it fails silently. It also states that WPML has no API for adding languages and routes the agent to the WPML screen, and prescribes the follow-up sequence (create pages, then wordpress_link_translations).

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