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

Annotations are limited (readOnlyHint=false, destructiveHint=false, openWorldHint=false), so the description carries some burden. It discloses that 'update' persists selectors, which is a useful behavioral trait. However, it does not explain whether update overwrites existing mappings, whether mainDomain is required, or how selectors relates to selectorSets. This leaves ambiguity about exactly what happens when updating.

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 two sentences and front-loads the core purpose. The first sentence states the action and resource; the second sentence gives action-specific usage. Every sentence earns its place with no redundancy or filler.

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?

The tool has a complex schema with conflicting-looking parameters (selectors vs selectorSets), a default surfaceId, and an optional mainDomain, but the description only explains action and the general concept of selectors. Even with an output schema present, an agent would not know which parameters to populate when updating or how selectorSets differs. The description is not complete enough for reliable 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 0%, so the description must compensate. It explains the meaning of action and broadly mentions GA4, Search Console, and Bing Webmaster selectors, but it does not clarify roles of name, surfaceId, mainDomain, selectors vs selectorSets, or how they interact with the update action. This is insufficient for a tool with 6 parameters and nested objects.

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 gets or updates persisted selectors for a website/app analysis surface, using a specific verb and resource. This distinguishes it from sibling tools like marketing_get_report or marketing_get_sources, which focus on reading analytics data rather than managing surface mappings.

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 clear, explicit guidance on when to use each action: 'get' to inspect mappings and 'update' to persist selectors. It does not mention alternative tools, but it provides enough context for the primary decision of which action to invoke. No exclusions are stated.

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