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

The description adds valuable behavioral context beyond the annotations: it explicitly states the change affects only Loomaly's settings, never the website, and mentions the page must be one Loomaly has found. It does not contradict annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=true). It lacks details on error handling or rate limits, but these are not critical for a simple setter.

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 concise and well-structured: it states the core action first, then the clearing option, then the prerequisite and scope. No wasted words, and it front-loads the primary use case.

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 two-parameter setter with no output schema, the description is largely complete. It covers purpose, page format, clearing, and scope. It omits an explanation of siteId and does not address potential error scenarios (e.g., invalid page), but these are minor given the tool's simplicity and the presence of idempotentHint in annotations.

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 50% (page has a description, siteId does not). The description adds little beyond the schema: it repeats the page format and null-clearing behavior but does not explain siteId at all. It also adds the 'page must be found' constraint, but that's not a parameter format. With low coverage, the description should compensate for the missing siteId documentation, which it fails to do.

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 clearly states the tool's purpose: setting the focus page for the week, with explicit mention of clearing via null. It distinguishes itself from the sibling 'focus_page' (which likely retrieves the current page) by indicating this is the setter. The scope ('Changes Loomaly's settings only') further clarifies its role.

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 provides clear context on when to use this tool (to set or clear the focus page) and even specifies the page format (URL, path, or ID). It also notes a prerequisite (page must be found by Loomaly). However, it does not explicitly name alternative tools or state when not to use it, though the 'focus_page' sibling implies a getter.

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