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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds useful behavioral context: 'nothing is scheduled and publishable is always false,' and explains what the return value shows (kind and quote card). This goes beyond the safety profile without contradicting it.

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 four sentences, front-loaded with the core purpose. Each sentence adds value: purpose, read-only guarantee, return values, and follow-up usage. No wasted words.

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?

Given the tool's simplicity, rich annotations, and presence of an output schema, the description covers purpose, usage, and behavior well. The only gap is the lack of explanation for the 'substackConnectionId' parameter, but overall it provides enough for an agent to call the tool 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 description coverage is low (33%). The description compensates for the 'url' parameter by specifying it's a public Substack Note or post/article link, but it does not explain 'substackConnectionId' at all. Partial compensation keeps it at a minimum viable level.

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 specific verb (Check) and resource (public Substack Note link or Substack post/article link), and clearly frames the purpose as previewing before quoting. It distinguishes itself from scheduling tools by noting that schedule_note or schedule_notes should be used to actually schedule the quote.

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 clear context on when to use (before quoting) and how to proceed afterward (pass the link as quoteUrl to schedule_note or schedule_notes). It does not explicitly state when not to use or name an alternative tool for the same preview purpose, but the guidance is strong enough for correct invocation.

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