describe_table

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds value by specifying the exact return contents (key schema, indexes, billing mode, item count, size) and the status values, which is useful beyond the annotations.

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 for purpose, usage, and returns. It is longer than the minimal example but every sentence provides useful information and it is front-loaded with the main purpose.

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 tool is a simple read-only describe operation with one parameter and an output schema, the description is thorough: it covers what data is returned, when to use it, and alternatives. No critical gaps.

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?

There is only one parameter, table_name, which has a clear description in the schema. The tool description doesn't explicitly mention the parameter but the context ('about a DynamoDB table') makes it obvious. Schema coverage is effectively high, so baseline 3 is appropriate.

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 verb+resource: 'Get detailed information about a DynamoDB table's schema and configuration.' It clearly lists the returned elements and explicitly distinguishes from sibling list_tables by saying when NOT to use it.

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 includes explicit 'When to use' and 'When NOT to use' sections with concrete scenarios (e.g., checking key schema before querying, verifying GSIs, checking status) and names the alternative tool (list_tables). This is exactly the level of guidance required.

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