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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, which the description does not contradict. The description adds value beyond annotations by listing precisely what the call reveals (agents, manifests, checklist, config, next steps), and the schema description adds that the owner is derived from the authenticated principal.

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 zero filler: the question front-loads the purpose and the second sentence enumerates the return payload in a scannable list. Every clause carries information.

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 zero-parameter, read-only status tool with an existing output schema and rich annotations, the description covers what the agent needs: what it returns and that it takes no arguments. No critical usage detail is missing.

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?

The tool has zero parameters, which earns the baseline 4. The schema description goes further by stating 'No arguments — the owner is derived from the authenticated principal,' so an agent understands why no input is needed and how identity is resolved.

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 'Where am I in onboarding?', immediately clarifying that despite the 'start' name this is a status query, and specifies a concrete verb ('Returns') plus a specific resource: the user's onboarding state (registered agents, capability manifests, progress checklist, Base Sepolia config, available vs. pending actions). This content-level detail distinguishes it from siblings like check_earnings and data_preview.

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 opening question frames the exact use case: an agent that needs to know where it stands in onboarding. It does not name alternatives or state when-not-to-use, so it stops short of a 5, but the context is clear enough to route correctly.

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