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

Annotations indicate a non-read-only, non-idempotent, non-destructive operation (write). The description adds valuable behavioral details: the item always lands on a specific leg per the item's own ruleset, a mismatched ruleset confirms via 400, and the caller must have a specific permission. It also clarifies that the ruleset param never retargets. These go beyond annotations and help the agent predict outcomes and errors.

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 tight and front-loaded. The primary action is in the first sentence, followed by two concise sentences that cover the most critical behaviors (leg matching, ruleset confirmation, permission). No filler, no redundancy beyond the schema's own param descriptions, and every sentence 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 description covers the core behavior, error conditions, and authorization, which is sufficient for an add operation. It does not address possible duplicate handling or idempotency, but the presence of an output schema and annotations reduces the burden. It's reasonably complete, with minor gaps around edge cases like re-adding an existing item.

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 100%, with each parameter well-documented. The tool description essentially repeats the schema's explanation of the ruleset parameter (confirm-only, mismatch → 400) without adding new meaning. While it reinforces the behavior, it does not elevate parameter understanding beyond what the schema already provides, matching the baseline for high coverage.

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, specific action: 'Add a vault item to a campaign's allowlist.' It identifies the resource (vault item), the destination (campaign's allowlist), and immediately provides a critical behavioral nuance (landing on the leg matching the item's own ruleset). This distinguishes it from sibling tools like play_add_campaign_character or play_add_campaign_rule by resource type, even 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 important usage context: the campaign must have a leg for the item's ruleset or the call fails with 400, and the optional ruleset param is purely confirmatory. It also states the required permission ('contribute' on the campaign). However, it does not explicitly mention when to prefer this tool over other add_campaign_* tools, nor does it list any exclusions, so it's not a full when/when-not guide.

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