list_tables

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds pagination support details (next_table_name) and notes the region scope, which goes beyond annotations. It doesn't mention rate limits or other edge cases, but for a simple read-only list operation, this is adequate.

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 clear opening sentence, a 'When to use' section, and a 'Returns' section. It is appropriately sized and every section serves a purpose, providing essential information without unnecessary fluff.

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 simple list tool with strong annotations and an output schema, the description is complete. It states the resource (DynamoDB tables), scope (AWS region), pagination behavior, and the return format (table_names, count, next_table_name). It also gives usage context relative to sibling tools, making it fully adequate for agent invocation.

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?

The input schema provides detailed descriptions for both parameters (limit, exclusive_start_table_name), so the agent has the needed semantics. The description adds context about pagination ('next_table_name for pagination') which complements the schema, but it doesn't explicitly explain the parameters themselves. Given the schema description coverage signal is 0% for the tool description, the description does not compensate fully, but the schema itself covers the parameters.

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 'List all DynamoDB tables in the configured AWS region' with a specific verb and resource. It distinguishes from siblings by noting it is a starting point for discovery before querying or scanning, and the 'When to use' section explicitly contrasts with describe_table, query_table, and scan_table.

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 an explicit 'When to use' section listing two concrete scenarios (discover tables, find a table name before using other tools). This clearly tells the agent when to use this tool versus alternatives, with no ambiguity.

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