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

Beyond the readOnly/idempotent annotations, it discloses non-obvious behavior: results are data-only and nothing is shown to the user until sightglass_show is called, plan-gated fields return null and are enumerated in each item's `locked` list, `lockedCount` signals truncated results, and the agent must tell the user the data is on a higher plan rather than estimating it. These are exactly the operational caveats annotations cannot express.

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 the payload description, then the result shape, then the show-it workflow, and every sentence carries information. It is dense and slightly long, but no sentence is filler.

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 carries the full burden of describing returns: field contents, null/locked behavior, lockedCount, and the required sightglass_show step. An agent has everything needed to call it, interpret the result, and render it correctly.

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%, so the defaults for from/to, the companyRef 'id or slug' note, and the workspace/project scoping are already documented in the schema. The description adds result semantics (discount steps) rather than parameter meaning, so the 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 gives a specific verb and resource ('A brand's offer campaigns'), enumerates what each campaign contains (deal type, date range, depth, ad/page counts, exact quote), and explains the grouping/steps logic. It is very clear what the tool returns, though it never distinguishes itself from the overlapping sibling sightglass_find_offers, which an agent must resolve on its own.

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 states concrete usage contexts ('answer what is this brand running', 'compare two brands' promotions') and gives an explicit follow-up workflow (call sightglass_show once with the resultId to render cards, noting show does not re-search). It stops short of saying when to prefer this over find_offers, but the when-to-use guidance is otherwise clear.

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