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

With no annotations, the description carries the burden. It discloses the dependency on connected account, the return shape (blocklist identifiers and total_count), and cost in tokens. It implies a read-only list operation; not stating auth/rate limits is acceptable for a simple list.

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 concise sentences, leading with the action, then usage prerequisite, return values, and cost. No filler or redundant 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?

For a straightforward list endpoint with fully documented parameters and an output schema, the description covers prerequisite, instance selection, return contents, and cost. It is complete without unnecessary elaboration.

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 input schema already provides descriptions for all three parameters (100% coverage). The description adds context about how to obtain the clerk_instance_id and the default behavior, but does not significantly extend the schema's explanation of limit/offset.

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 uses a specific verb (List) and resource (blocklisted identifiers), clearly distinguishing this from sibling operations like create_blocklist_identifier or list_allowlist_identifiers. The scope ('in a connected Clerk instance') and orientation (lists existing identifiers) are immediately clear.

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?

It provides explicit preface instructions: call clerk.get_connected_accounts first and how to either pass a specific inst_id or use the default. This gives clear usage context without explicitly contrasting against alternatives, but the purpose is self-evident.

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