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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and closed-world scope, so safety is covered. The description adds the useful return detail ('full block markup and attributes'), but says nothing about error behavior for out-of-range indexes or how nested blocks resolve.

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 tight sentences with the verb and scope front-loaded and the return value second. No filler, no redundancy.

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 small read tool with no output schema, the description covers purpose and return shape, and the schema covers all four parameters. Only the nested-block path routing and sibling boundaries are left unstated.

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 coverage is 100%, with per-parameter descriptions for index, path, post_id and site_id, so the schema does the heavy lifting. The description restates only the index semantics and does not explain the index-vs-path choice for nested blocks, so it adds nothing beyond the schema.

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 and resource: 'Reads a single Gutenberg block from a post by its zero-based index.' This clearly separates it from the write-oriented siblings (wp_update_block, wp_delete_block, wp_move_block) without naming them.

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 when-to-use guidance and no alternatives. It never mentions wp_list_blocks (which supplies the raw path used for nested blocks) or wp_read_post, so an agent must infer the boundary between reading one block versus listing or reading the whole post.

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