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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new context beyond that: 'does not advance the unread cursor,' which tells the agent a side effect it might otherwise assume. 'Idempotent' merely restates the annotation and it doesn't cover ordering or pagination, so it falls short of a 5.

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?

Front-loaded with the core action and result shape, and no sentence is wasted. The telegraphic phrasing of 'stay on campaign' is slightly opaque, costing a point on clarity, but the overall size is appropriate for a zero-param list tool.

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 no-parameter, read-only list tool with full annotation coverage and no output schema, the description covers purpose, sibling routing, and the one non-obvious side-effect caveat. Nothing an agent needs in order to call it correctly is missing.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline applies. The parenthetical field list usefully signals what each row contains, adding a little value without overreaching.

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?

States a specific verb and resource ('List Campaigns in this Space') and enumerates the returned fields (id, name, owner, status). It also explicitly contrasts with the sibling get_campaign, so an agent can distinguish the list tool from the single-row tool without opening either schema.

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?

Names the alternative ('Get one row with get_campaign') and the condition that selects it, and further routes mutation actions (open, park, resume, close, reassign_owner) to the campaign tool. This gives explicit when-to-use and when-to-use-something-else guidance with no inference required.

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