session_info

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

With no annotations provided, the description carries the full burden of behavioral disclosure. The verb 'Show' strongly implies a non-destructive, read-only operation, and the term 'live' adds context that it reflects the current state. However, it does not explicitly state that it has no side effects or what happens if no session exists, so it is not a perfect 5.

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 a single, well-structured sentence that front-loads the core action ('Show the live Spark session') and then lists the details. Every word adds value, and there is no redundancy or irrelevant information.

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?

This is a simple zero-parameter tool with an output schema. The description fully conveys what information is available, and the output schema provides the return structure. No additional context is needed for the agent to invoke this tool correctly.

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, so there is no schema detail to explain. The description still adds value by enumerating the specific information returned (version, master, current database, catalog databases, lakehouses), which gives the agent a clear picture of the tool's output even without parameter definitions.

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 uses a specific verb ('Show') and clearly identifies the resource (live Spark session) and its key contents (version, master, current database, catalog databases, lakehouses). This makes the tool's purpose unambiguous and distinguishes it from siblings like run_code and run_sql, which execute code rather than introspect the 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 implies the tool is for inspecting current session state, which provides clear context for when to use it. It does not explicitly mention alternatives or when not to use it, but the purpose is obvious enough that an agent can select it appropriately among the sibling tools.

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