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

No annotations are provided, so the description carries the full behavioral burden. It does disclose a non-obvious trait the schema cannot express: the $0.05 USDC (x402) payment requirement. However, it omits error behavior, handling of duplicate keys, and whether the operation is purely read-only analysis.

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?

A single tight sentence: the operation and its output are front-loaded, and the cost caveat is appended last where it belongs. Zero filler.

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?

With no output schema, the description must convey the return shape, and it does so compactly (added/removed/changed plus changed columns). The pricing disclosure is a bonus. Minor gaps remain around tie-breaking/duplicate keys and payment flow, but the essentials for correct invocation are present.

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 67%, with before/after fully described and keyColumns partially. The description adds the concept of matching 'by key' and clarifies the output relates changed rows to their changed columns, but adds no format or constraint detail beyond the schema. 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?

Specific verb (compare) plus resource (two versions of a table) plus the exact output shape (rows added, removed, changed with changed columns). It is clearly distinguishable from siblings like deduplicate (which operates on one table) and convert_to_csv. An agent can select this without opening the schema.

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 comparison semantics imply when the tool applies, but there is no explicit when-to-use, when-not-to-use, or named alternative among the siblings. Prerequisites (both tables must share key columns) are only implied by the required params. Minimum viable guidance.

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