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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description usefully adds that the call is 'Free' (no cost/auth barrier), which is context beyond the annotations. It does not discuss rate limits or output shape, so it stops short of 5.

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?

Two sentences, zero waste: the first front-loads what the tool is and returns, the second handles routing. Nothing is redundant with the name or annotations.

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?

For a no-param, no-output-schema discovery tool with full annotation coverage, the description gives an adequate summary of the return categories and how to proceed afterwards. It is essentially complete; only a slightly richer sense of the return structure would push it higher.

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, so there is no argument semantics to explain and the baseline for a no-param tool is 4. The description correctly implies the tool is a zero-input discovery call.

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?

States a specific verb and resource ('capability map for PaidHandshake Exchange') and enumerates exactly what it returns: feed families, machine endpoints, payment rails, and operating rules. It is clearly distinguishable from siblings like get_machine_wallet or get_machine_onboarding without opening any 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?

Explicitly says 'Use this first' and names two alternatives with the conditions that select them: get_machine_onboarding for enrollment/setup and get_machine_wallet for authenticated balance/limits. This is a textbook when-to-use / alternative routing statement.

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