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

Beyond annotations, the description discloses a significant side effect: 'Calling this marks onboarding complete.' It also explains the tool does not persist data itself but instructs the agent to save with penny_write, and that the client parameter tailors the returned snippet. This adds meaningful behavioral context not available from readOnlyHint/idempotentHint/destructiveHint alone.

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 deliver all essential information: purpose, return content, side effect, precondition, and parameter guidance. The longest sentence is dense but every clause earns its place, and the most critical side-effect warning ('only call it when the user agrees to set up') 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?

With no output schema, the description fully explains the return values (interview script and snippet) and the follow-up action (save with penny_write). It covers side effects, preconditions, and parameter behavior, making it complete for an agent to decide when to call and what to do afterward.

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 schema already documents the `client` parameter at 100% coverage. The description adds practical context about when to pass it ('when you know which app the user is in') and why ('to tailor the paste-here instructions'), which goes beyond the schema's basic type and enumeration guidance.

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: 'Run the first-run setup interview with the user.' It then details exactly what is returned (interview script plus custom-instructions snippet), clearly distinguishing this tool from siblings like penny_read, penny_write, and penny_session_start.

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 gives an explicit trigger condition: 'only call it when the user agrees to set up.' It also references checking penny_read target:'profile' meta.onboarded to understand state. However, it does not explicitly state exclusions like 'do not call if already onboarded' or name alternatives such as penny_session_start for ongoing conversations.

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