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

Annotations already establish readOnlyHint=true/destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: message text is shortened in the response, and results/per-campaign totals live in campaigns_list — a real data-limitation caveat an agent needs to avoid misreporting.

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 lead phrase 'Everything about one campaign' is front-loaded and the routing sentence and truncation caveat are well placed. The middle enumeration is a long run-on list that overlaps with sibling setter names and could be tightened, but every element does describe a returned field, so it earns most of its length.

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?

With no output schema, the description correctly compensates by enumerating the returned structure, and it adds the important truncation caveat plus the pointer to campaigns_list for totals. Only minor gaps remain (no mention of error cases for an invalid/foreign campaignId), which is acceptable for a simple single-item read.

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% and campaignId is already documented as 'as returned by campaigns_list', so the schema fully carries the parameter. The description adds no format, sourcing, or constraint detail beyond it — baseline 3.

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 ('Everything about one campaign') and then enumerates the exact contents returned: trigger, watched post, keywords, messages, buttons, links, and each switch. This is clearly distinguishable from the sibling setters (campaigns_set_*) that mutate those same fields.

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?

Explicitly routes the agent: 'Use it after campaigns_list when someone asks what a particular campaign says or does, or why it is not firing.' It names the sibling to call first and the two motivating conditions, with no need for inference.

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