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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds the partial-update semantic, a genuine behavioral trait beyond the annotations, but says nothing about permissions, what happens to omitted fields, or the meta merge behavior.

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?

Two short sentences with zero filler, front-loaded on the action, followed by the key partial-update constraint. Appropriately sized, though not ambitiously informative.

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 an 8-parameter mutation tool with a nested meta object and no output schema, the description covers the core action but omits how meta should be shaped, what rest_base values are valid, and the meaning of the status enum. Annotations carry the safety story, so a minimum-viable 3 is fair.

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 50% (id, meta, site_id, rest_base documented; title, status, content, excerpt bare). The description only vaguely refers to 'fields' and adds no syntax or format detail beyond what the schema provides, so it does not compensate for the undocumented half.

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 (update a custom post type item) and scopes it to 'any custom post type.' It is distinguishable from siblings like wp_update_post and wp_create_custom_post by the 'custom post type' qualifier, though it never explicitly names those siblings as alternatives.

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?

'Only provide fields you want to change' gives real usage guidance for a partial-update call, which is more than nothing. However, it offers no when-to-use-vs-alternative routing (e.g., when to use this instead of wp_update_post), and no prerequisites are stated.

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