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

Annotations already carry readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the read-only nature is covered. The description adds useful behavioral context: output is readable EIP-191 text, the heartbeat has a 30-minute window, and the owner must review and sign. It does not contradict any annotations.

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 with no filler. The core action, the nature of the artifact, the duration, and the signing workflow are all packed concisely and 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 two-parameter tool with a rich output schema and safety annotations, the description covers the main workflow and duration. It could explicitly mention how the tokenId/owner map into the EIP-191 text, but the output schema reduces that need.

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 description coverage is 100% and both parameters are documented in the input schema. The description adds marginal context by implying the owner wallet is the reviewer/signer and the token ID is tied to the NFH heartbeat, but it does not at significant parameter-specific detail beyond the schema.

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 clear, specific action: prepare readable EIP-191 text for a 30-minute public presence heartbeat. It also distinguishes this from delegated heartbeat tools by emphasizing the owner wallet reviews and signs, which separates it from prepare_agent_presence_delegation and prepare_delegated_agent_heartbeat.

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 implies the usage context: the owner wallet needs signable text for a public presence heartbeat before signing. However, it does not explicitly state when to prefer this tool over siblings like prepare_delegated_agent_heartbeat or prepare_agent_presence_delegation, leaving the selection partly to inference.

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