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

Annotations (idempotentHint=true, destructiveHint=false) already establish safety; the description digs deeper by clarifying that `public_url` and `image_url` are read-only in this tool and that `image_url` is the creator's profile avatar rather than a page image. This prevents an agent from attempting to mutate fields that appear mutable. No contradiction with annotations — description says 'Update' (write) and readOnlyHint=false, consistent.

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 front-loaded sentences with no waste. The core intent leads, and each subsequent sentence defuses a distinct misconception (read-only URL, avatar caveat, missing theme field). Efficient and well-ordered.

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 simple 4-param update tool with full schema coverage, idempotent/non-destructive annotations, and no output schema, the description covers what is updatable, what is explicitly off-limits, and where the exceptions live. The only mild gap is not naming the sibling tools by name, but nothing an agent needs to invoke it correctly is missing.

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% and the schema documents all four params (id, name, slug, description). The description adds value by clearing up domain confusion: it explains that `slug` is the public URL handle and warns that `public_url`/`image_url` from the broader API are read-only here, so they are not targetable via this tool. It goes beyond the schema to prevent misuse.

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+scope: 'Update page title, bio, or public URL handle.' This is unambiguous and matches the sibling family (split_update_link, split_update_profile, split_update_section). It doesn't explicitly name a sibling it is not, but the resource 'page' plus the field list makes the purpose clear.

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?

Provides explicit when-not guidance: `image_url` is read-only here and image changes need an upload this tool does not do, and there is no theme/colour field since appearance is set per-section. This tells an agent when to look elsewhere, though the alternative tools (e.g., split_upload_page_image, split_update_section) are implied rather than explicitly named.

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