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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description adds further context: discloses the exact return shape, a $0.005 cost, and the rationale of preventing wasted credits. This enriches behavioral understanding beyond the annotations without any contradiction.

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 sentences: purpose, return details + cost, and usage timing. Every sentence adds value, no fluff, and the purpose is front-loaded.

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 simple one-parameter tool, the description fully covers the return format, cost, prerequisite action, and rationale. No output schema exists, but the description handles that by explicitly showing both possible return shapes.

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 100%, providing baseline. The description adds extra guidance on where to find the target_agent_id ('Find agent IDs on the Hall of Agents or via x711_agent_reputation'), which goes beyond the schema's basic UUID description.

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 opens with a specific verb and resource: 'Check if a target agent has PingShield before pinging.' It immediately distinguishes itself from sibling tools by referencing x711_agent_ping and x711_agent_reputation, making the tool's unique role clear.

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 states when to use: 'Always call this before x711_agent_ping when targeting unknown agents.' It also provides an alternative for checking one's own score: 'Use x711_agent_reputation to check your own score.' This gives clear context and exclusions.

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