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

Annotations already declare readOnlyHint/destructiveHint, and the description goes well beyond them with status-aware branching: drafts yield activation blockers matching the checks activation enforces, paused campaigns yield pause reason + reason-specific fix + resume viability, active campaigns yield silent-stop detection plus next send time in Eastern time. It also discloses the blocker output format (what/why/how/action with the fix tool), which is substantial behavioral disclosure not available in annotations or schema.

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-loads the trigger phrase ('use whenever...'), then behavior, then the output contract. Dense and information-rich, with every sentence contributing, though the long compound trigger sentence and 'CAMPAIGN DOCTOR' branding add slight bulk without new information.

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 carry return semantics, and it does: it explains what is returned per campaign status and the what/why/how/action structure of each blocker. An agent has everything needed to call it and interpret the result.

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 omit-to-auto-pick fallback logic). The description adds nothing about the parameter, so the baseline of 3 applies where the schema does all the work.

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 verb+resource (diagnose a campaign) and frames it as a 'CAMPAIGN DOCTOR', which clearly separates it from data-fetching siblings like get_campaign/get_campaigns and from state-changing siblings like activate_campaign/pause_campaign. An agent can tell what this does without opening any schema.

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?

Gives unusually rich trigger conditions: 'use whenever the user asks why a campaign won't start, can't activate, is paused, stopped sending, isn't working, or what's wrong with its settings.' It does not, however, name explicit alternatives (e.g., get_campaign for raw config) or state when NOT to use it, so it falls just short of the when/when-not/alternatives bar.

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