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

Annotations already establish non-destructive, idempotent mutation, so the description earns credit for what it adds beyond them: the patch semantics of 'only the fields you pass change' and the side effect that renaming relocates the goal's page URL. It stops short of stating permission/premium requirements or what the response returns, so it is not exhaustive.

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?

Three short sentences, front-loaded with the action and field list, followed by the two highest-value caveats (patch semantics, URL change). Nothing is padded or redundant.

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 not be described, and the annotations cover the safety profile. Combined with the field enumeration, patch semantics, and rename side effect, an agent has everything needed to call this 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?

With 50% schema description coverage the description meaningfully compensates by naming every mutable field and mapping 'target' and 'impact tiers' to targetAmount and impact. It still does not explain the required 'id' semantics (whose goal) or clarify the unit/limits already partially noted in the schema.

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?

Opens with a specific verb+resource ('Change a goal') and enumerates the mutable fields (title, target, description, deadline, impact tiers), which cleanly separates it from create_goal, delete_goal, get_goal, and list_goals in the sibling set. The extra note that renaming moves the goal's own page address makes the scope 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?

'Only the fields you pass change' is a clear partial-update contract that tells the agent how to invoke it safely. However, it never names an alternative or a when-not condition (e.g., use set_active_goal to change active state, or get_goal first to read current values), so alternatives are left implicit.

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