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

Annotations already cover read-only/non-destructive behavior, so the description doesn't need to repeat that. It adds useful behavioral context: the session-linkage check, the guardrail against processing rental requests when disconnected, and the live-number card display.

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 short sentences with the main purpose front-loaded; the second sentence delivers actionable branching logic and the third adds output context. No filler or redundancy.

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 zero-parameter, read-only status check with an output schema, the description covers invocation timing, the failure branch, and what the user may see. Nothing essential 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 has zero parameters and schema description coverage is 100%, so there is nothing for the description to clarify. No parameter-level explanation is needed.

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?

States a specific operation: 'Check whether this ChatGPT session is linked to Ucode.' The description clearly identifies the resource and expected result, and the conditional reference to ucode_render_home separates it from related auth/session tools.

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?

Explicitly says 'Use at chat start' and provides a concrete conditional rule: if connected is false, run ucode_render_home and do not process rental requests. This is a clear when/when-not guideline for an agent.

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