open_session

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

No annotations are provided, so the description carries the full disclosure burden. It hints at session warming and verification but says nothing about resource consumption, concurrency limits, whether an opened session must be closed with close_session, or what the permission_mode/'dangerous' option implies. For a stateful session-creation tool this leaves major behavioral gaps.

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?

One tight sentence with the action and the purpose front-loaded and no filler. It is efficient, though the compression contributes to the under-specification of an unusually parameter-rich tool.

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?

With 13 parameters, no annotations, no output schema, and sparse schema descriptions, the definition is far too thin. An agent cannot tell what a returned session handle looks like, how long the session lives, or how it interacts with close_session and session_turn.

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?

Schema description coverage is only 23% (roughly workspace, read_paths, write_paths), leaving ten parameters such as agent, model, effort, permission_mode, include_active, and conversation_id documented nowhere. The description adds no parameter meaning at all, so it fails to compensate for the coverage gap.

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 gives a clear verb and resource ('Open a ... session') and implicitly positions the tool in a lifecycle alongside siblings like session_turn and close_session. It also names the rationale (low-latency multi-turn work). It does not explicitly contrast itself with those siblings, and 'verified warm stream-json session' is jargon that only partly clarifies what is actually created.

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 clause 'for low-latency multi-turn work' implies when to reach for this tool (repeated turns where latency matters) rather than a one-shot cli_execute. However, it never states prerequisites, when-not-to-use, or names any alternative tool such as cli_execute or session_turn, so the selection guidance must be inferred.

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