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

Beyond the annotations (which only declare it a safe, idempotent read), the description discloses plan-gating behavior in detail: locked fields return null, are named in each item's `locked` list, `lockedCount` reports hidden results, and the agent must say the data is on a higher plan rather than estimate it. It also states the tool returns data only and requires a separate sightglass_show call with resultId — critical non-obvious behavior.

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?

It is front-loaded with what a campaign is and what fields come back, then moves to usage and the show-flow. It is dense and long-ish, but nearly every clause carries operational information (locked fields, resultId handoff, no self-estimation).

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 must carry the return-shape burden, and it does: campaign contents, grouping/steps semantics, locked fields, lockedCount, and the two-step display flow. An agent has everything needed to call it and to interpret and present the result.

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 the schema already documents every parameter including date defaults and the companyRef/workspaceId conventions. The description adds only a loose 'from when to when' notion of the date range, so it neither compensates nor detracts — 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 uses a specific verb and resource ('A brand's offer campaigns') and enumerates what each campaign contains (deal type, dates, depth, ad/page counts, source quote). It doesn't, however, distinguish this from the sibling sightglass_find_offers, which an agent could easily confuse with campaigns.

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?

It gives concrete usage contexts: "Use it to answer 'what is this brand running' or to compare two brands' promotions," and explains the follow-up sightglass_show step. It stops short of stating when to prefer it over sightglass_find_offers or sightglass_find_ads, so the routing guidance is incomplete.

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