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

No annotations are present, so the description carries the burden. It discloses that it updates settings, returns the updated communication settings, and notes a cost of 8 tokens, but lacks details on side effects (e.g., whether existing blocked country codes are replaced or merged) or required permissions.

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?

Four short sentences, front-loaded with the main purpose, and no fluff. Every sentence adds value including the cost and return behavior.

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 has an output schema and full parameter coverage, the description is adequate. It includes cost, usage prerequisites, and return behavior, but could mention the effect of omitting blocked_country_codes (e.g., keep existing settings), though the schema already provides defaults.

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 100%, so both parameters are already documented. The description adds a small amount of context for clerk_instance_id (omit for default account), but this is also in the schema, so it does not significantly enhance parameter understanding beyond the schema.

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 'Update SMS communication settings for a connected Clerk instance' using a specific verb and resource, clearly distinguishing it from sibling update_instance_* tools by focusing on communication settings.

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?

Provides explicit usage guidance: 'Call clerk.get_connected_accounts first' and explains how to target a specific connection via clerk_instance_id or use the default account. It does not discuss alternatives or when not to use this tool, but the context is clear.

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