session_start

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

With no annotations, the description carries the full burden of explaining side effects. It discloses that sessions record cad() mutations as transactional steps, that execute_code steps are non-atomic, and that rollback behavior is affected. This goes beyond a simple 'start session' statement and gives important behavioral context.

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 well-structured with a clear opening sentence, a paragraph explaining side effects, and a concise Args/Returns section. It is front-loaded and every sentence adds value with no fluff.

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?

The description covers the main purpose, side effects, and return value (session info). However, the required doc_name parameter is not explained, which is a notable gap. For a tool with moderate complexity, the description is otherwise thorough enough for an agent to invoke it correctly if it can infer doc_name from context (e.g., 'bound to a document').

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 description explains 'name' and 'create_document' clearly, but it completely omits 'doc_name', which is the only required parameter. The schema only labels it as 'Doc Name', which is minimal. This is a gap that could confuse an agent since the description does not explicitly bind the session to that document.

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 clearly states the tool's purpose: 'Start a modeling session bound to a document.' This provides a specific verb (start), resource (modeling session), and binding context. It distinguishes itself from sibling session tools like session_pause, session_rollback, and session_complete, which handle different lifecycle operations.

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 explains when to use the tool by mentioning 'enabling session_rollback for trial-and-error modeling.' This implies usage for iterative modeling workflows. It does not explicitly mention alternatives or when not to use it, but the context is clear enough in relation to the sibling tools.

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