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

With no annotations, the description carries the transparency burden. It discloses that the operation returns an updated email address summary and includes a cost of 8 tokens, but it doesn't explain potential side effects (e.g., implications of setting primary or verified) or permission requirements. Some behavioral context is provided, but not comprehensive.

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 only four sentences and every sentence serves a purpose: stating the action, giving a prerequisite, explaining scoping, and noting the return value and cost. It is front-loaded and free of unnecessary detail.

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 100% schema coverage and presence of an output schema, the description adequately round out the tool by adding the prerequisite connection step and return summary. It could mention error scenarios or the exact fields affected, but for a straightforward update tool this is largely complete.

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 the schema already documents all parameters. The description adds a bit of clarity around clerk_instance_id usage, but largely restates what's in the schema. It doesn't add meaning beyond the existing parameter descriptions.

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 a Clerk email address by id' with a specific verb and resource, clearly distinguishing it from siblings like create_email_address, get_email_address, and delete_email_address. The 'by id' qualifier adds precision.

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 clear context by instructing users to 'Call clerk.get_connected_accounts first' and explaining how to use clerk_instance_id to target a specific connection or default. It doesn't explicitly mention alternatives or when-not-to-use, but the prerequisite and scoping guidance are useful.

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