Simulate a session (sandbox)

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

The description adds value beyond annotations by explaining that the simulation involves no telco, no purchased extension, and no charge. It details the loop behavior and end condition. Annotations already declare readOnlyHint=false and destructiveHint=false, and the description is consistent with those.

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: two sentences. The first sentence states the purpose and key benefits, the second explains the usage pattern. No unnecessary words.

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?

Given the tool's moderate complexity and lack of output schema, the description is mostly complete. It explains the simulation flow and end condition. However, it does not describe the response structure beyond the 'action: end' field, which is notable for an iterative 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?

The input schema has 100% coverage with descriptions for all 6 parameters. The description adds context for the interaction pattern (how to use new_session and input together), but does not significantly enrich parameter meaning 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 it drives a USSD session against one of your own apps in test mode. It uses the specific verb 'drives' and identifies the resource as a USSD session, distinguishing it from sibling tools like send_sms or get_session.

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 step-by-step usage: open with new_session=true and empty input, then repeat with same session_id and next input until action: end. It also notes the requirement for the ussd scope. However, it does not explicitly contrast with other USSD tools like hellio_ussd_get_session or hellio_ussd_list_sessions.

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