bulk_add_items

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

Even though annotations already indicate non-read-only, idempotent, and non-destructive behavior, the description adds substantial context: uses batch_writer, 25-item batches, automatic retries on unprocessed items, flushing, and overwrite semantics for duplicate primary keys. It also discloses the return format. This goes well beyond the annotation hints.

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 a lead sentence, a short technical detail paragraph, bulleted usage guidelines, and a return statement. Every sentence adds value, and there is no verbose filler. It is front-loaded with the primary action and remains readable.

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 bulk write tool with output schema and annotations, this description is comprehensive. It covers the operation's purpose, batching behavior, retries, overwrite semantics, exclusions (single item, conditional writes), and return value. Combined with the schema and annotations, an agent has everything needed to correctly invoke and interpret the 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?

Context signals indicate low schema coverage (0% at top level), so the description must compensate for parameter meaning. It does so by explaining that items are written in batches of 25, that duplicate primary keys overwrite, and that the return is a count. However, it does not explicitly describe the table_name parameter or the exact structure of items beyond primary key requirement. The nested schema does provide descriptions for items and table_name, partially offsetting this gap.

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 opens with a specific action: 'Add multiple items to a DynamoDB table in efficient batches.' It clearly identifies the resource (DynamoDB table) and the scope (multiple items, batch efficiency). It also differentiates from sibling tools by explicitly referencing add_item for single-item use cases, making the tool's purpose 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 provides explicit 'When to use' and 'When NOT to use' sections. It names add_item as the alternative for single items and highlights that conditional writes are unsupported, giving clear boundaries for when bulk_add_items is appropriate. This is exactly the guidance needed for agent selection.

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