list_indexes

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

No annotations exist, so the description carries full burden. It discloses that the tool returns sizes and scan usage statistics for health evaluation, indicating a read-only, analytical behavior. While it doesn't detail internal implementation or performance impact, the provided information is sufficient for an agent to understand the tool's non-destructive, information-returning nature.

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 a single, well-structured sentence. It front-loads the action (List), specifies the resource (indexes on tables), and adds value (with sizes and scan usage statistics to evaluate index health). No unnecessary words or repetition.

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 absence of an output schema, the description skillfully conveys the tool's purpose and key return data (sizes, scan usage statistics). It is complete enough for an agent to decide when to call it among 12 siblings. A minor gap: it could explicitly list the output fields for total clarity, but the health evaluation context compensates.

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 baseline is 3. The tool description ('with sizes and scan usage statistics to evaluate index health') adds overall context but does not provide new semantic information about the two parameters beyond what the schema already describes (optional table filter and schema name with default).

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 lists indexes on tables with specific return fields (sizes and scan usage statistics) and a clear purpose (evaluate index health). This distinguishes it from siblings like list_tables (tables), list_foreign_keys (foreign keys), and suggest_indexes (suggestions, not listing).

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 implies usage for evaluating index health but provides no explicit guidance on when to use this tool versus alternatives like suggest_indexes or get_table_stats. No when-not or exclusion criteria are mentioned, leaving the agent to infer context.

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