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

With annotations indicating a non-read-only, non-idempotent, non-destructive operation, the description adds valuable context: it explains the tool is 'pure preparation — no keys, no signing, no spending on our side,' outlines the funding flow, and clarifies that creating the account costs a network fee to Hedera. It also states the human signs once and can revoke later. These details go beyond the annotations and help the agent understand the behavioral implications.

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?

The description is lengthy and includes both a 'first principles' explanation and a 'how to explain it to your human' script. While the information is relevant, it is not front-loaded for quick scanning; the core mechanics are buried after motivational content. Some sentences could be trimmed without losing essential guidance.

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?

The tool has no output schema, so the description should explain return values; it does so by mentioning 'You get back a setup_url'. It covers prerequisites, key requirements, funding details, and the human's role. The main missing piece is a description of what the setup_url leads to (though it is partially described) and any potential error conditions. Overall, it is nearly complete for the agent to call correctly.

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%, so the schema already documents all parameters. The description reinforces some parameter meanings (e.g., 'pass its intro_claim_code here', 'Pass your agent's ED25519 PUBLIC key as 64-char hex') but does not add substantial new semantics beyond what the schema provides. Baseline 3 is appropriate when the schema is comprehensive.

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 clearly states the tool's core action: preparing a shared vault account for the agent, with the goal of enabling solo action after a single human signature. It distinguishes itself from siblings like post_agent_intro by specifying that an intro must exist first, but it does not explicitly contrast with prepare_agent_claim or prepare_vault_page.

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 provides a clear prerequisite: 'you must have posted your intro with post_agent_intro first' and explains the required parameter. It also tells the agent to send the returned setup_url to the human. However, it does not explicitly say when to use this tool versus alternatives like prepare_agent_claim or prepare_vault_page.

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