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

With no annotations, the description carries the full burden and does so well: it discloses destructive replacement semantics for accounts, the failure conditions (100% share overflow, missing exchange rate, fixed-amount shortfall), plan prerequisites, and the return shape. These are the kind of side effects and constraints an agent needs before mutating state.

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?

Front-loaded with the core action and update semantics, then failure modes, prerequisites, and return shape. Dense but nearly every clause earns its place; only the enumerated failure list is a touch long, though it is high-value.

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 9-parameter mutation with no annotations and no output schema, the description is complete: it covers partial-update behavior, replacement semantics, failure conditions, prerequisites, and explicitly names the return shape (get_goals shape). An agent can call it correctly without further inference.

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 100%, so the baseline is 3, but the description adds genuine value beyond the schema: it explains that accounts replaces the entire set and that status drives pause/archive/restore, which the schema enumerates but does not explain consequentially. This lifts it above baseline.

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 and resource ("Update a savings goal") and the partial-update semantics ("Only passed fields change") distinguish it from a full create. It does not explicitly name create_goal/delete_goal as alternatives, but the verb is specific and 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?

Provides clear context for use: partial field updates, accounts full-replacement behavior, and status to pause/archive/restore. It also states a prerequisite (Goals feature or active trial). No explicit when-not or named-alternative routing, so it falls short of a 5.

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