update_campaign

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

With no annotations provided, the description fully covers behavioral traits. It discloses that the tool only works on draft campaigns and returns errors otherwise. It states that only provided fields are updated while omitted fields remain unchanged, clarifying the partial update behavior. It also mentions authentication via API key, Mailchimp rate limits (max 10 concurrent requests), and respect for read-only/dry-run modes.

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?

The description is well-structured with clear sections: main purpose, constraints, authentication, Args, Returns, and an Example. It is front-loaded with the core functionality. However, it is somewhat lengthy (approximately 20 lines). While every sentence adds value, a slight reduction in verbosity could improve conciseness for the same information density.

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?

Given the complexity (8 parameters, 0% schema coverage, no annotations) and the presence of an output schema, the description is complete. It explains all parameters thoroughly, describes the return JSON structure, provides usage constraints, and includes a realistic example. The description also addresses authentication and rate limits, leaving no essential gaps for an AI agent to use the tool 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?

Despite 0% schema description coverage, the description provides detailed parameter explanations in the Args section. Each parameter is defined with its purpose, constraints (e.g., reply_to must be a verified domain), and dependencies (segment_id requires list_id). It also gives examples of how to obtain certain parameter values (campaign_id, list_id, segment_id) and includes a full example call with expected return value.

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 clearly states the tool updates settings or segment targeting of an existing campaign draft. It specifies the exact fields that can be modified (subject line, sender, segment targeting) and distinguishes itself from 'set_campaign_content' which changes the HTML body. The verb 'Update' and resource 'campaign' are specific and unambiguous.

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?

The description explicitly states when to use (modify settings before sending) and when not to (only works on draft status, not sent/scheduled). It provides an explicit alternative: 'Use set_campaign_content to change the HTML body instead.' It also gives prerequisites (obtain campaign_id from list_campaigns or create_campaign) and mentions authentication and rate limits, guiding proper invocation.

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