YNAB Auth Status

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds that it reflects server-side configuration state (credentials + write-tool gating), which is useful context, but it says nothing about whether the check itself needs network access or what it reports when unconfigured — the output schema presumably covers the latter.

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?

A single front-loaded sentence with no filler; both facts it surfaces appear before any potential truncation point.

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 check with an output schema and full annotation coverage, the description supplies everything needed: what is being checked and why the answer matters (write-tool availability). No further detail would change how an agent invokes it.

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 takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies; the description correctly does not waste words on non-existent inputs.

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?

States a specific verb ('check') and two concrete facts it reports: whether credentials are configured and whether write tools are enabled. No sibling tool in the list touches authentication/discovery, so it is unambiguous, though it never explicitly contrasts itself with siblings such as preview_write_tool.

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?

Usage is only implied: mentioning 'whether write tools are enabled' hints that this is the pre-flight check before any write attempt or the diagnostic for auth failures, but there is no explicit 'call this when...' or 'do not call this to...' statement.

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