get_nav_history

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

Annotations already establish readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds real behavioral context beyond that: values are read from the chain at past blocks rather than live, and the series is bounded by the vault's deployment date. It does not discuss sampling cost or how reorgs/past-block reads are handled, but the essential traits are disclosed.

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 sentences, front-loaded with what the tool returns and followed by the data-window constraint and comparison use case. Slightly dense in the opening clause, but no sentence is 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?

With an output schema present, the description need not enumerate return fields, and it correctly focuses on data provenance and window semantics. Combined with full parameter documentation and annotations, an agent has enough to call this correctly; only the ambiguity against analytical siblings remains.

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% – both 'points' (2-90, default 30) and 'interval' (hour/day, default day) are documented in the schema, including defaults and the 'newest last' ordering. The description adds nothing about the parameters, 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 names the specific resource and metric (NAV per GBLIN share over time) plus the bundled series (ETH/USD and BTC/USD oracle prices, window change, max drawdown). It is unambiguous about what comes back. It does not explicitly contrast with any sibling, though no sibling covers NAV history, so the risk of confusion is low.

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: 'can be compared with holding ETH or BTC over the same span' suggests an analyst comparing vault performance against benchmarks. There is no explicit when-to-use, when-not-to-use, or named alternative among siblings such as get_treasury_state or analyze_treasury_health, which an agent would have to disambiguate on its own.

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