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

With no annotations, the description carries the full burden. It discloses the prerequisite call, instance targeting behavior, that a summary is returned, and includes 'Cost = 8 tokens.' This goes beyond the schema. However, it omits potential edge behaviors (e.g., duplicate handling, required permissions), which a fully transparent description could include.

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 compact and well-structured: purpose first, then prerequisite/parameter guidance, return value, and cost. Every sentence serves a functional purpose with no filler. The cost line is an efficient addition.

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?

The tool operation is simple, and the description covers purpose, prerequisite, instance selection, return, and cost. An output schema exists, so return details are covered. Minor gaps remain around when to choose this over blocklist tools and potential duplicate behavior, but overall it is sufficiently complete for a 3-parameter creation tool.

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 coverage is 100%, so the baseline is 3. The description adds meaningful context for clerk_instance_id by explaining when to pass it and the default behavior, and it stresses calling get_connected_accounts first. This nudges the score above baseline, though it does not elaborate on identifier or notify 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 clearly states the tool's action: 'Add an identifier to the allowlist in a connected Clerk instance.' The verb 'Add' and resource 'identifier to the allowlist' are specific, and the phrase 'allowlist' distinguishes it from the sibling create_blocklist_identifier tool. The mention of 'connected Clerk instance' scopes it appropriately.

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 usage context: 'Call clerk.get_connected_accounts first' and explains how to use clerk_instance_id (pass to target a specific connection, omit for default). However, it does not explicitly state when to use this tool over alternatives (e.g., vs create_blocklist_identifier), so it falls just short of a 5.

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