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 that data is stored in our own DB (not a connected-tool write-back), that pacing is intentionally not persisted, that an existing slot's target is superseded with history retained, and that it should confirm in one line afterward. These are rich, non-obvious behavioral traits.

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-loads purpose then constraint/trigger detail in dense, mostly non-redundant sentences. It is on the longer side, but nearly every clause (currency rule, storage location, supersede behavior, confirmation step) earns its place; minor tightening is possible.

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 mutation tool with no annotations and no output schema, the description covers what is stored, what is not stored, currency/store constraints, unit semantics, and the post-save expectation. Nothing essential for correct invocation is missing.

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 real meaning: money metrics MUST be scoped via `store` (currency reason), targetValue is in MAJOR units (80000 = £80k), and period attaches to the CURRENT period of that type. It only omits the odd `_offset` parameter, which the schema itself covers.

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+resource ('Store a merchant's GOAL for a metric over a calendar period') with a concrete example. It explicitly distinguishes itself from the read-side sibling get_targets by noting pacing is never stored here. An agent can tell exactly what this does versus get_targets.

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?

Gives an explicit TRIGGER ('whenever the user states a target/goal/budget for a metric') and clarifies the read counterpart ('pacing ... computed later on read by get_targets'). It also notes this is not a write-back to a connected tool, ruling out a plausible misinterpretation.

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