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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true, so the safety profile is covered. The description adds real behavioral context by explaining the done toggle (true stays done when money is spent, false reopens), which annotations cannot convey. It does not, however, state that this is a partial update (unlisted fields are left alone), what archiving actually does to the goal, or any permission requirements.

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?

It is front-loaded with the mutation list and every clause earns its place, with no filler. The first sentence is a run-on with nested parentheticals that is harder to scan than a per-field list would be, but the density is justified by the number of undocumented parameters.

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 an 11-parameter mutation tool with no output schema and zero schema-level documentation, the description covers amounts, dates, and most fields — enough for correct invocation. The remaining gaps (id, icon, color, archiving side effects, partial-update semantics) are real but secondary, and no return-value documentation is required since there is no output schema.

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 0% schema description coverage across 11 parameters, the description carries the full burden and mostly succeeds: it defines units (minor units, 45000 = 450.00), date format (YYYY-MM-DD in the family time zone), month format (YYYY-MM), and the null semantics for deadline and monthly. It omits three parameters entirely — id, icon, and color (the latter carrying a 16-value enum) — so the compensation is strong but incomplete.

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 names a specific verb (change/update) and enumerates the exact mutation surface of the resource: rename, target, deadline, months, monthly amount, account, done, archived. This makes it unambiguous against siblings such as create_goal, delete_goal, and apply_goal_cuts, which an agent can rule out without opening 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?

Usage is only implied: the field list tells the agent what can be changed, but there is no explicit when-to-use statement, no exclusions, and no routing to alternatives (e.g. create_goal for a new goal, reorder_goals for ordering, delete_goal for removal). The null-value rules for deadline and monthly are value semantics rather than tool-selection guidance.

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