Fund NAV History

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds only that results are paged, without saying what the page/size defaults are or how many rows to expect, which limits its added value beyond the annotations.

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?

A single compact sentence with the core purpose front-loaded and the parameter hints trailing. Nothing is padded or redundant.

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, paged list tool with full schema coverage and no output schema, the description covers the essentials an agent needs to invoke it. The only gap is the lack of sibling disambiguation against fund_nav / fund_nav_range.

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 four parameters already carry their own documentation, including the counter_id example and the _jq filter semantics. The description only restates counter_id's source and the optionality of page/size, adding no syntax or format detail 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 historical NAV series, paged' — so the agent knows this returns a time series rather than a snapshot. It does not, however, differentiate itself from close siblings like fund_nav or fund_nav_range, which an agent could easily confuse with it.

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 gives one piece of provenance guidance — counter_id comes from fund_hot / fund_list — but offers no when-to-use or when-not-to-use relative to fund_nav, fund_nav_range or fund_nav_history-style siblings. Usage is implied rather than stated.

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