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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds the output fields but does not describe behavioral details such as whether pending invites are included, ordering, or authentication requirements. This is acceptable but not a strong addition beyond annotations.

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?

A single sentence that front-loads the action and resource, then adds the meaningful output components. There is no filler or repetition of schema field names.

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 read-only list tool with one parameter idempotent to call, the description plus annotations and output schema are sufficient. The agent knows what it lists, what fields are surfaced, and that the call is safe to make.

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%: the only parameter, campaignId, is documented as a Mongo `_id`. The description adds no parameter-specific detail, but the schema already carries the full semantic burden, so the baseline of 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 specific verb and resource: 'List the players in a play campaign' and adds the fields returned (roles, invite status, per-player flags). It is clear, but it does not explicitly distinguish itself from sibling tools like play_list_campaign_characters or play_list_campaign_sessions, so it earns a 4 rather than a 5.

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 intended use is implied by the name and the one-line description, but there is no explicit guidance about when to use this tool versus other campaign list tools or exclusions. It is not misleading, but it leaves the agent to infer usage from context.

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