wp_set_featured_image

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

No annotations are provided, so the description must disclose behavioral traits on its own. It only says 'Assign' without mentioning that this overwrites an existing featured image, whether it requires authentication, what happens on invalid ref/media_id, or how dry_run affects execution. These are meaningful side effects an agent needs to know.

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 description is a single, front-loaded sentence with no filler or repeated information. It communicates the core purpose efficiently and every word contributes to meaning.

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?

This is a mutation tool with no annotations and no output schema, yet it leaves key invocation details undocumented: what ref accepts, behavior of dry_run, overwriting semantics, and failure scenarios. An agent cannot reliably predict the tool's full behavior from this description alone.

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 only 25%, so the description carries the burden of explaining parameters, but it only clarifies that the operation applies to a 'post or page' (matching post_type). It does not explain that ref is likely a post/page ID or slug, what media_id refers to beyond being 'media', or the role of dry_run beyond the schema's terse text.

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 specific action ('Assign') on a specific resource ('media attachment') and where it applies ('as the featured image of a post or page'). It clearly distinguishes this from sibling tools like wp_update_media or wp_get_post, since no other tool appears to handle featured-image assignment.

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?

The description gives no guidance on when to use this tool versus alternatives, nor does it mention prerequisites such as the post/page existing or the media attachment being uploaded. With dozens of sibling tools around posts and media, the lack of any routing or exclusion information leaves the agent to infer usage from the name alone.

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