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

Annotations already establish readOnly/idempotent/non-destructive, so the bar is lower, and the description adds real value beyond them: it promises the full object with every field and current value, states it round-trips with the update call, and pre-empts a likely misinterpretation of autoFulfillRewards:false. It does not cover auth/permission needs or rate limits.

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?

Front-loaded with the purpose, then the return shape, then the caveat and the targeting rule. Every clause carries information an agent needs; the parenthetical enumeration is dense but earns its space by naming the configurable sub-areas.

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 an output schema present the description need not describe return values, yet it helpfully states the shape is write-back compatible. Target selection and default are covered. Only minor gaps remain (auth requirements, whether a program must already exist), and none would block a correct call.

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 100% and the single campaignId parameter is fully documented in the schema, including the GROWSURF_CAMPAIGN_ID default. The description restates the same targeting rule ('Targets campaignId if you pass it, otherwise GROWSURF_CAMPAIGN_ID') without adding syntax or format detail, so the baseline of 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?

Specific verb ('Fetch') plus specific resource ('Options tab configuration for your GrowSurf program'), and it enumerates the sub-areas the Options tab covers (triggers, anti-fraud, affiliate enrollment, notifications, languages). This distinguishes it clearly from siblings like growsurf_get_campaign and growsurf_update_campaign_options.

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?

Usage is implied rather than stated: 'the same shape you send back on update' anchors it as the read-side partner of growsurf_update_campaign_options, and the autoFulfillRewards note warns against a wrong inference. But there is no explicit when-to-use/when-not guidance or named alternative for cases where a different getter is appropriate.

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