Inflation by CPI group

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the lower bar applies. The description adds genuine value by disclosing the returned metrics (index, monthly change, point_to_point_pct, 12-month average), which matters because there is no output schema. It stops short of noting units, group coverage, or ordering.

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?

Two short paragraphs, front-loaded with the action and scope, followed by a compact return-value summary and the routing note. Every clause carries information; there is no filler.

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 two-parameter, annotation-covered read tool with no output schema, the description supplies both the routing rule and the shape of the result, which is the main gap an agent would otherwise face. Minor omissions (units, whether all groups are always returned, default-month behavior already in schema) keep it from a 5.

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 description coverage is 100%, with both `period` (YYYY-MM format, omit for latest) and `region` (enum of national/urban/rural) fully documented in the schema. The description only reinforces the one-month scope and the `group` reference without adding syntax or edge-case detail, so the baseline 3 applies.

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 gives a specific verb and resource ('Compare official inflation across CPI groups') and enumerates the group examples (food, housing, transport, health). It also names the sibling that serves a different purpose (am_inflation with `group` for one group's multi-month history), so an agent can distinguish the two without opening either 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?

It states the intended use case ('see what drives inflation') and explicitly routes the alternative case to am_inflation with the `group` parameter. The single-month scope constraint versus multi-month history is spelled out rather than left to inference.

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