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

Annotations already provide idempotentHint=true, destructiveHint=false, and readOnlyHint=false. The description adds that the tool updates the 'authenticated user's' settings, implying authentication requirements. It does not elaborate on side effects or idempotency, but the annotations cover the key safety traits.

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 no wasted words. Front-loaded with purpose, then usage guidance. Very concise.

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 simple update tool with a comprehensive schema and output schema, the description covers purpose and usage guidelines adequately. It does not mention return values (but output schema exists) or prerequisites beyond 'authenticated user'. Minor gap: could explicitly state that only the authenticated user's settings are affected.

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 has 100% description coverage for all 4 parameters. The tool description adds no additional parameter meaning beyond what the schema already provides. Baseline score of 3 is appropriate.

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 verb 'Update' and the resource 'account settings' for PocketLedger defaults, listing specific fields (expense currency, reporting currency, timezone, locale). It also distinguishes from sibling tools by explicitly excluding transaction edits, wallet balances, payments, and subscriptions.

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 explicit when-to-use ('account preferences only') and when-not-to-use ('not transaction edits, wallet balances, payments, or subscriptions'), helping the agent decide. It does not name alternative tools directly but the exclusion list is clear.

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