find_direct_joins

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

The description implies a read-only operation by stating 'Return' and clarifies bidirectional join detection. With no annotations provided, the description carries full burden; it does not disclose potential side effects, permissions, or edge cases (e.g., no joins found), nor does it explain the output structure beyond referencing FK-defined joins.

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 extremely concise, using only two sentences to convey the core purpose and usage format. It front-loads the main action and provides a concrete example, with no unnecessary words.

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 three required parameters, no annotations, and an output schema, the description is inadequate. It fails to explain the 'source' parameter, does not compare with sibling tools like suggest_joins, and omits error handling or default behavior. The output schema exists but that does not compensate for missing usage context.

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 coverage is 0%, so the description must compensate. It partially does by specifying the format for table_a and table_b. However, the 'source' parameter is left completely unexplained, and the schema provides no descriptions either. This leaves ambiguity about what 'source' refers to.

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 returns FK-defined direct joins between two tables, including the 'either direction' detail. However, it does not differentiate from sibling tools like list_all_foreign_keys or suggest_joins, which may have overlapping functionality.

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 a specific format for table names ('schema.table') with an example, which helps correct usage. However, it lacks guidance on when to use this tool versus alternatives, and does not mention prerequisites or context for the 'source' parameter.

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