get_trend_series

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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds a scope constraint ('one historical item') and specifies the metrics ('rank and hot-value'), but it does not disclose any additional behavioral traits such as authentication requirements, rate limits, or data handling. This is acceptable given the annotations, but the description itself provides only marginal extra value.

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?

The description is a single sentence that is front-loaded with the action and subject. There is no wasted words or redundancy. It is appropriately concise for a straightforward getter tool.

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?

Despite having an output schema (which reduces the need to describe return values) and rich annotations, the description is incomplete for a tool with 6 parameters. It does not explain how the parameters interact (e.g., that since/until define the time range and bucket controls granularity), nor does it clarify what 'historical item' implies about required identifiers. The description is too minimal to fully guide correct invocation.

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 0%, meaning the schema provides no descriptions for parameters. The description must compensate but does not. It only mentions 'rank and hot-value trends,' which relates to the output, not the meaning of parameters like site, board_key, since, until, and bucket. The agent is left to infer parameter semantics from names and defaults, which is insufficient for a 6-parameter tool.

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 clearly states the tool's function: 'Get rank and hot-value trends for one historical item.' The verb 'Get' is specific, the resource ('rank and hot-value trends') is concrete, and the scope ('for one historical item') differentiates it from sibling tools like query_history or search_history, which likely handle broader queries.

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 implies a use case (retrieving trends for a single item) but provides no explicit 'when to use this vs alternatives' guidance. It does not name any sibling tools or describe when this tool would be preferred over others like fetch_current or query_history. The usage context is only implied by the phrase 'historical item,' which is a weak form of guidance.

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