Twin status

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

Annotations already declare readOnlyHint=true and openWorldHint=false, and "Changes nothing" reinforces the non-mutating nature. More valuable is the disclosure of what the response contains across nine state areas — behavior an agent cannot learn from any output schema here, since none exists.

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?

Two sentences, no filler: the state inventory comes first and the call-to-action second. Every clause carries information the agent can act on.

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 burden of explaining what comes back, and it does so thoroughly. Only minor gaps remain — whether the listing is truncated or paginated, and how 'timeline entries due next' is bounded.

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 nothing for the description to disambiguate; the baseline of 4 applies. The description wisely spends its words on returned state instead of non-existent inputs.

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 specifically what the tool reports — an enumerated inventory (company, seed, loaded scenario, twin time, event count, auth mode, faults, checkpoints, upcoming timeline entries) — so the agent knows exactly what state snapshot it returns. It is clearly distinct from siblings like twin_changes or twin_webhooks by that enumeration, though it never names an alternative explicitly.

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?

"Call it first to get your bearings" gives concrete sequencing guidance that tells the agent when to reach for this tool. It stops short of naming when *not* to use it or pointing at alternatives, so it is strong but not complete.

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