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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so safety is fully covered elsewhere. The description adds two genuinely useful facts beyond the annotations: there are 'No arguments' and the call costs 'no credit', plus that the data is 'fixed synthetic', implying deterministic output. It stops short of describing the shape of the returned recipe.

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?

Three short sentences with the core deliverable front-loaded, and no filler. The 'mode' clause is the one line that neither earns clarity nor fits the no-argument reality, keeping it from a 5.

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?

There is no output schema, so the description carries the burden of explaining what comes back; it names the return ('fixed synthetic left/right tables and a reusable join recipe') but not the actual structure an agent would copy. Combined with the unexplained 'mode' reference, an agent has enough to call it but not a fully coherent picture of the output.

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?

Zero parameters means the baseline is 4, but the description creates confusion rather than clarity: it first asserts 'No arguments', then says 'mode controls which unmatched rows appear in output'. Since the schema exposes no mode property, this sentence reads as internally inconsistent and risks misleading the agent about whether a mode argument exists. That ambiguity pulls the score below the 0-param baseline.

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 states a specific verb and resource: it returns 'fixed synthetic left/right tables and a reusable join recipe', which is far more concrete than the title alone and tells the agent this is a template-producing tool. It distinguishes itself from the mutation-oriented reconcile_tables it feeds, though it does not explicitly contrast with its closest sibling, get_csv_example.

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?

'Copy the structure for reconcile_tables' implies the intended workflow (grab the example, then model a real join on it), which is useful routing context. However, it never states when to choose this over get_csv_example or view_table_demo, and gives no exclusions, so usage is only implied rather than specified.

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