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

Annotations already declare non-destructive, idempotent, non-read-only behavior, so the bar is lower. The description still adds real value by explaining the mechanism ('puts the others away without deleting anything') and explicitly flagging reversibility, which clarifies that other goals are deactivated rather than removed.

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?

Two tight sentences, front-loaded with the primary action and immediately followed by the side effect and reversibility note. No filler, every clause carries information.

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?

An output schema exists so return values need no explanation, and annotations carry the safety profile. The description covers the single-active-goal model and reversibility, though it could note that a missing/absent id leaves no goal active; still adequate for a 2-param mutation tool.

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 50%: 'active' is documented in the schema, while 'id' is not. The description's 'turn the current one off' maps onto the active=false case but does not add format or meaning beyond what the schema already states, so the id gap remains uncompensated. Baseline 3 fits.

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 (make active / turn off) and resource (goal shown on page), and clarifies scope against siblings like update_goal and delete_goal by noting nothing is deleted. An agent can distinguish this from create_goal, update_goal, and delete_goal without opening schemas.

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?

Implies when to use it via 'The page shows a single goal at a time, so choosing one puts the others away,' which explains the consequence of the action, but it never explicitly contrasts with alternatives such as update_goal (to edit goal content) or list_goals. Usage is inferable rather than stated.

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