bulk_send

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behavioral traits: cost deduction upfront, automatic refunds for failed cards, volume pricing based on tier, and the 500-recipient limit. However, it doesn't mention authentication requirements, rate limits, or what happens if the balance is insufficient.

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 perfectly concise and well-structured: three sentences that each earn their place by covering purpose, constraints, and financial implications. It's front-loaded with the core functionality and wastes no words.

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?

For a mutation tool with no annotations and no output schema, the description does a good job covering the essential context: what the tool does, key constraints, and financial implications. However, it doesn't describe the return value or error conditions, which would be helpful given the absence of an output schema.

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 100%, so the schema already documents all parameters thoroughly. The description adds minimal value beyond the schema by mentioning that recipients, message, image, and return address are the key components, but doesn't provide additional semantic context about parameter usage or constraints beyond what's in the schema.

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's purpose: 'Send the same postcard to multiple recipients at once' with specific details about what remains constant (message, image, return address) and what varies (recipient addresses). It distinguishes from the sibling 'send_postcard' by emphasizing bulk functionality with a maximum of 500 recipients.

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 provides clear context for when to use this tool: for sending identical postcards to multiple recipients. It mentions the 500-recipient limit and volume pricing, but doesn't explicitly state when NOT to use it or name alternatives like 'send_postcard' for single recipients.

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