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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), yet the description still adds real value: snapshot ordering ('oldest first'), timestamp units (unix seconds), value units (USD, human-readable not raw), and the crucial interpretation that an empty history is not a failure. It stops short of mentioning any cap on the `days` window or whether the series is paginated/truncated for long ranges.

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?

Three short sentences, front-loaded with the core action, then output shape, then an edge-case clarification. Nothing is redundant and the empty-history note earns its place by preventing a false-negative interpretation.

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?

With an output schema present, the description need not restate structure, yet it still disambiguates the two fields an agent would most likely misread (unix seconds, USD human-readable) and explains the empty-result case. Nothing needed to invoke or interpret the call correctly 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 description coverage is 100% — all three parameters (account_address, days, chain_id with its chain list) are fully documented in the schema. The description adds no parameter-level detail beyond that, so the baseline of 3 is appropriate; its unit clarifications describe the response, not the inputs.

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 — historical net value for an Arcadia account — with scope (over time, time series of snapshots). It is clear what the tool does, but the close sibling read_account_pnl (also an account-metric time read) is never named, so an agent must infer the boundary from tool names alone.

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?

Usage is only implied through 'Useful for charting account performance over a period,' which gives a motivation but no rule for when to pick this over read_account_pnl or read_account_info. No exclusions or prerequisites are stated.

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