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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds genuinely non-obvious consequences: renaming breaks the old web address with no redirect, and changing the target does not re-evaluate goal completion. These are exactly the side effects an agent needs to warn about before calling.

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 sentences, front-loaded with the field list, then partial-update semantics, then the two caveats. No filler, and each sentence carries distinct, actionable 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 the description covers all mutable fields plus their side effects. It omits permission/Premium requirements and behavior when the id does not exist, which is a minor gap for a six-parameter mutation.

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 only 50%, so the description must compensate, and it does: it names all five optional fields and adds meaning the schema lacks (impact replaces the entire list rather than merging, renaming mutates the URL, target edits skip completion checks). It does not clarify id semantics or the Premium gating on impact, so it falls short of a 5.

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 (change/update) plus the resource (a goal) and enumerates the mutable fields: title, target, description, deadline, impact tiers. This clearly separates it from create_goal, delete_goal, get_goal, and list_goals without needing to open any schema.

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 gives useful operational context ('Only the fields you pass change, and each replaces the old value') which tells the agent how to invoke it, but never states when to choose this over siblings like create_goal or delete_goal, nor any prerequisites or exclusions. Usage is implied by the field list rather than spelled out.

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