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

Beyond the annotations (openWorldHint, non-idempotent, non-read-only), the description discloses that the work happens off-tool in the user's browser, that a free photo check runs as a side effect, and that a sensitive connection_key is returned which must be retained for account tools and never shown to the user.

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?

Three tight sentences, front-loaded with the primary purpose, then the returned link, then the connection_key handling rule. No filler and no repetition of the title or annotations.

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?

With no output schema and no parameters, the description carries the full burden of explaining what comes back, and it does: a user-facing link and a secret connection_key with lifecycle instructions. There is no information an agent needs to invoke or follow up on this tool that is missing.

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 tool takes zero parameters, so there is no parameter semantics to explain and the baseline expectation is met. The description correctly spends its words on return values and usage instead.

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 names the concrete outcome ('Start here to make photos') and describes the mechanism: it returns a link the user opens to sign in or sign up to TrueLook and upload 1-4 selfies. This clearly separates it from siblings like create_photos, account_status, and disconnect_account.

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 gives explicit entry-point guidance ('Start here'), a call-frequency rule ('Only call this once per conversation unless the key stops working'), and an exception condition. The agent knows both when to call it and when not to call it again.

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