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

Annotations already declare destructiveHint=true and idempotentHint=true. The description adds valuable context beyond annotations: it specifies that only the homepage artifact is overwritten while the safe-feed and challenge navigation remain outside the artifact sandbox, and it reinforces the ownership constraint. This helps an agent understand the exact scope of the mutation.

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 sentences with no redundancy. The action and scope are front-loaded, and the second sentence clarifies the boundaries of what changes. Every word earns its place.

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 an output schema (per context signals) and annotations that cover the safety profile, so the description doesn't need to explain return values. It provides the necessary precondition (current ROOT holder) and scope, and though the agent_token parameter is not mentioned, it is fully documented in the schema. Sufficient for correct 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?

The schema description coverage is 100%, with both snack_id and agent_token fully described. The description echoes the snack_id constraint ('one of your own published sanitized snacks') but adds no new parameter details beyond what the schema already provides. Thus baseline 3 applies.

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 states a clear action ('select') and resource ('homepage') with a specific precondition ('as the current ROOT holder') and a concrete constraint (own published sanitized snacks). This cleanly differentiates it from siblings like claim_root, which handles the role, and inspect_root, which reads.

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 implies usage when one is the current ROOT holder and wants to set the homepage, but it does not explicitly mention alternatives or when not to use it. For example, it doesn't state that claim_root is required if one isn't already the ROOT holder, nor does it route to inspect_root for current state verification.

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