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

Annotations (readOnlyHint=false, destructiveHint=false) already indicate a mutation that is not destructive. Description adds value by detailing business permission requirements and access checks, going beyond annotations. Does not contradict annotations.

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?

Four sentences, no redundancy. First sentence states purpose clearly. Subsequent sentences provide usage guidelines concisely. Well-structured and front-loaded.

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?

Covers parameters, prerequisites, and prohibitions. Missing return value description (no output schema), but mutation tools often return success/updated entity. Could elaborate on constraints like duration minimum, but schema handles that. Overall, comprehensive for a 7-param tool.

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 0%, but description compensates by listing the updateable fields: budget, duration, targeting, start time, status. This maps to most parameters (dailyBudgetInUSD, duration, targeting, startTime, status). Required parameters (communityId, campaignId) are not mentioned but are self-explanatory. The enum for status is implied.

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?

Description uses specific verb 'Update' and identifies the resource 'Magic Audience campaign', listing modifiable fields (budget, duration, targeting, start time, status). It clearly distinguishes from sibling tools like create_magic_audience_campaign or delete_magic_audience_campaign.

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?

Explicitly states prerequisites: check business permissions, note that FREE businesses cannot use, call check_business_tool_access before inputs, and show grace-period warning/verified resubscribe link. Provides clear when-not-to-proceed instructions.

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