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

Beyond the readOnlyHint/idempotent annotations, it discloses non-obvious behavior: fields outside the plan come back null and are enumerated in each item's `locked` list, `lockedCount` signals withheld results, and the agent must tell the user the data is on a higher plan rather than estimate it. It also states explicitly that nothing is shown to the user until sightglass_show is called with the resultId.

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 dual-mode framing before the plan/locked caveats and the show workflow, and nearly every sentence carries actionable information. It is dense and runs long, but the length is justified by the number of distinct behaviors being disclosed.

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 and 8 optional parameters, the description still tells the agent what comes back (items with `locked` lists, `lockedCount`), how to present results (sightglass_show once with resultId), and how plan gating affects output. Nothing an agent needs to invoke or follow up 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?

Schema coverage is 88%, so the schema already documents most parameters and the baseline is 3. The description adds genuine semantics the schema lacks: companyRefs presence switches mode, and sort's three values map to concrete meanings (most ads, longest running, deepest discount) with trailing-window framing for `days`.

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 names a specific resource (offer campaigns across brands) and splits behavior into two clearly labeled modes ('top' with no companyRefs, 'calendar' with them). It goes well beyond restating the title, though it does not explicitly contrast itself with near siblings like sightglass_find_campaigns or sightglass_find_ads, which an agent could confuse it with.

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 user-intent triggers ('what offers are working in this market', 'when do these brands run sales') and an explicit rule selecting mode based on whether companyRefs is supplied. The follow-up instruction to call sightglass_show with the resultId, and the note that show does not re-search, closes the loop on next steps.

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