describe_table

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

Annotations set readOnlyHint=true, which is consistent with the description stating 'Reads the cache.' The description goes beyond annotations by noting that the tool 'Raises if the table is not found,' adding important error behavior. It also implies that the cache must be populated first, which is useful context.

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 three sentences: first sentence clearly states purpose, second details the output components, third gives usage guidance and mentions a prerequisite and error condition. Every sentence adds value without redundancy.

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 no output schema, the description adequately summarizes the return content (columns, defaults, comments, foreign keys, incoming references). It also covers error behavior and usage context. However, it does not specify the exact structure or format of the output, which could be helpful for agents expecting a detailed 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?

Input schema has 100% coverage: each parameter has a description. The tool description adds minimal extra value for parameters; it mentions that table_name should be 'as shown by list_tables,' which is a slight addition. Baseline is 3 due to high coverage.

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: 'Describe one cached table in detail, including its foreign-key relationships.' It specifies the exact verb (describe), the resource (one cached table), and the scope of detail. This distinguishes it from sibling tool list_tables which returns a list of all tables.

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 usage guidance: 'Use when you need a single table's keys to write a join; for a list of all tables use list_tables.' It also mentions a prerequisite: 'Reads the cache (introspect first).' This clearly tells the agent when to use this tool versus alternatives.

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