update_stack

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

With no annotations, the description carries the full burden of behavioral disclosure. It explicitly states the side effect ('updates the stack on the server') and the input constraint on primary_asset_id, which goes beyond the raw schema. It does not cover error behavior or permissions, but for a simple non-destructive update the disclosure is adequate.

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 short, front-loaded with the core purpose, and uses a compact Args block followed by a Returns line. Every sentence contributes necessary information without redundancy or filler.

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 two-parameter tool with an output schema, the description covers purpose, side effects, parameter meanings, a key validation constraint, and the return type. It lacks explicit notes on error handling or authorization, but that is a minor gap given the tool's simplicity.

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 0%, so the description must provide all parameter meaning. It does this fully: stack_id is 'The stack to update' and primary_asset_id is 'The asset that should become the cover' with the important precondition that it already belongs to the stack.

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: 'Change which asset fronts a stack', and clarifies the domain effect with '(the one the library shows)'. This clearly distinguishes the tool from sibling stack operations like create_stack, list_stacks, get_stack, and delete_stack.

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 context for when to use this tool: when updating which asset serves as the stack cover. It also gives a precondition ('It must already belong to the stack'), but it does not explicitly name alternatives or when-not-to-use conditions.

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