Fund Trend

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description's only added behavioral signal is that the response is a chart series, which is useful given there is no output schema, but granularity, period semantics and response shape remain undisclosed.

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 sentences with no filler, and the core purpose plus the key parameter source are front-loaded. It is efficient, though arguably so terse that it sacrifices needed context.

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 simple read-only, 3-parameter tool this is minimally adequate. With no output schema, however, the description should say more about what the returned series contains and how period selection affects it; it leaves that to 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 description coverage is 100%, so all three parameters (counter_id, period, _jq) are already documented, giving a baseline of 3. The description restates the counter_id source and period optionality but adds no syntax, format, or allowed period values beyond the schema.

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 ('Get a fund's trend chart series'), which is clearer than the bare name and separable from siblings like fund_nav_history or fund_performance. It stops short of explicitly differentiating itself from those similar nav/performance siblings.

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 points to where the required counter_id comes from (fund_hot / fund_list), which is practical context, but says nothing about when to choose this tool over fund_nav_history, fund_nav_range, or fund_performance. Usage is only implied by the 'trend chart' framing.

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