colab_session_list

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

With no annotations at all, the description carries the full burden, and it does deliver real behavioral context: the exact fields returned and two named failure modes (AUTH_EXPIRED, CLI_ERROR). It stops short of stating ordering/pagination or confirming the operation is strictly non-mutating.

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 lines, front-loaded with the single action sentence, then structured Returns/Raises blocks. Nothing is padded and the caller's two questions (what do I get, what can go wrong) are answered immediately.

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-param, no-annotation tool, the definition covers purpose, return shape and error modes. An output schema exists, so the Returns block is mildly redundant, and it omits whether stopped sessions are excluded from 'active' or how many sessions can come back.

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?

Zero parameters, so there is nothing to disambiguate — baseline 4 applies. The description correctly implies no filtering is possible, since it lists all active sessions unconditionally.

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 verb and resource ('List all active Colab sessions') with a clear scope qualifier ('active'). The plural 'all' implicitly contrasts with colab_session_get, but the description never names that sibling, so differentiation is inferred rather than stated.

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?

Usage is only implied by the enumeration semantics of 'List all active' — an agent can infer this is the discovery/entry-point call before colab_session_get or colab_code_execute. There is no explicit when-to-use, when-not-to-use, or alternative named.

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