Initialize a SKILL.state session

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

With no annotations provided, the description carries the behavioral disclosure burden. It discloses the stateful side effect of creating a session, storage of immutable P and initial state Σ_0, the returned initial payload, and the lack of message history. This goes beyond the schema and materially changes how an agent should treat the tool's effects.

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 sentences with no filler. The first sentence establishes the action and result, and the second provides the critical behavioral constraint that the agent must follow. Every sentence earns its place and the most important information is front-loaded.

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 there is no output schema and no annotations, the description covers the essential operational facts: what is created, what is stored, what is returned, and how the session should be advanced. The rich input schema handles parameter-level details, while the description supplies the workflow context an agent needs 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?

Schema coverage is 100%, so the baseline is 3, but the description adds meaningful semantic context by linking skill_specification to 'immutable skill specification P' and initial_state to Σ_0. It also emphasizes that this payload becomes the entire conversational context, which clarifies the significance of those parameters beyond their schema descriptions.

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 opens with a specific verb and resource: 'Create a new SKILL.state execution session.' It clearly explains the tool's role as the session initializer, distinct from subsequent advancement. It also names what the tool returns and what it stores, making its purpose unambiguous.

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 clear usage context by stating that after initialization the payload is the LLM's ENTIRE context and 'Advances happen exclusively through execute_step.' This explicitly routes subsequent behavior to a sibling tool. It does not discuss inject_observation, parse_turn_response, or close_session, but for initialization the key alternative is covered.

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