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

Annotations already mark this as a write operation (readOnlyHint=false). The description adds valuable behavioral context: excerpt is plain-text-only and auto-derived if omitted, and structured fields must go in meta rather than excerpt — details not present in annotations. It doesn't cover return behavior, but an output schema exists to handle that.

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?

Three sentences that lead with the core purpose, then add two crucial caveats. No wasted words, no repetition of schema field descriptions. The structure is front-loaded and focused.

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 tool with 16 parameters and a complex nested block schema, the description correctly highlights the key preconditions and pitfalls without drowning in detail. It references sibling tools needed for setup, and the output schema handles return values, so the description is complete for invocation.

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 the schema fully documents all 16 parameters. The description reinforces a couple of key constraints (excerpt plain-text, meta for structured fields) that are already in the schema, but adds no new semantic meaning beyond what the schema provides. Baseline 3 is appropriate.

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 opens with 'Create a new CMS post (blog_post, page, or any custom post type),' clearly stating the action and resource. It differentiates from sibling tools like update_post, delete_post, and list_posts by focusing on creation, and references related setup tools to avoid confusion.

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?

Explicitly states the prerequisite that the post type must already exist, and names list_post_types and create_post_type as the tools to discover or add post types. It also directs custom field schema definition to create_post_type_field, giving clear when-to-use and alternative guidance.

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