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

Annotations already cover the read-only/idempotent/non-destructive safety profile, and the description adds substantial behavior beyond that: plan-gated fields return null and are named in the item's `locked` list, `lockedCount` counts additional higher-plan results, and the caller must not estimate locked data. It also discloses that the tool returns data only ('nothing is shown to the user yet'), which is critical workflow context.

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?

Dense but nearly every sentence carries required information (mode logic, sort options, plan-locking, show workflow, resultId). It is front-loaded with the resource and mode split, though the single flat block could be broken into clearer segments.

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?

There is no output schema, so the description must explain results — and it does, covering the locked/lockedCount fields, the null-for-unauthorized-plan behavior, and the resultId handoff to sightglass_show. For an 8-parameter research tool with no required params and zero annotation-sourced return info, this is complete enough to invoke 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 coverage is 88%, so most parameters are documented in the schema; the description adds cross-parameter semantics the schema cannot express — that presence/absence of companyRefs toggles mode between 'top' and 'calendar' — plus the plan-gating/`locked` semantics tied to projectId/workspaceId. This is meaningful added value over the per-field descriptions.

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 resource (offer campaigns across brands) and clearly delineates two distinct behaviors: 'top' mode without companyRefs and 'calendar' mode with companyRefs. An agent can tell this is an offer-discovery tool, distinct from sibling ad/angle/campaign finders.

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 two concrete user intents it serves ('what offers are working in this market', 'when do these brands run sales') and maps each to the mode selected by whether companyRefs is supplied. It also explicitly routes the follow-up step to sightglass_show with resultId, so the agent knows the full call sequence.

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