Advanced: open a raw session

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

The annotations only mark readOnlyHint=false and openWorldHint=false, so the description carries most behavioral weight. It adds meaningful context: the operation is internal/advanced, session plumbing is normally hidden, and visible effects appear only when the receipt chain is requested. This is useful, though it does not detail side effects or lifecycle requirements.

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 two short sentences with no filler. The advanced/internal status is front-loaded, the preferred alternative is immediate, and the usage condition is stated efficiently. Every phrase contributes.

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 internal tool with no output schema, the description gives enough to decide when to call it and what to expect at a high level. It could name related lifecycle tools like runtime_session_close or runtime_session_receipt, but the core context is present and not misleading.

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?

There are zero parameters, so the description has no parameter burden to carry. The schema is fully covered by being empty; no additional parameter explanation is needed. The mention of 'session object' gives semantic context 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 states a specific action ('Open a raw session object') and immediately distinguishes itself from the preferred sibling ('Prefer fraggate_call'). The '[advanced/internal]' tag further clarifies it is a low-level alternative, so an agent can differentiate it from normal 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?

It explicitly names fraggate_call as the preferred alternative and gives a concrete condition for when the raw session is relevant: 'unless the user asked for the receipt chain.' This tells the agent both when not to use the tool and when the advanced path is justified.

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