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

Annotations already declare readOnly/idempotent/non-destructive/open-world, so the safety profile is covered; the description adds real behavioral value by stating the row model (per underlying, not per venue) and the exact metric set returned. It omits pagination/row-limit behavior and refresh cadence, which for a multi-venue aggregate would be worth knowing.

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?

Front-loaded with what the tool returns, then the filter values, then the sibling pointer — a sensible ordering. Dense but largely earned; the long enumeration of example underlyings (NVDA, TSLA, S&P 500, Gold, EUR/USD, Anthropic) is illustrative padding that could be trimmed, and the filter list duplicates the schema.

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 single optional-parameter read tool with no output schema, the description supplies the return shape, the venue scope, and the field set, which is enough to call it correctly. The gaps are the conflicting filter vocabulary and the undefined boundary with get_stocks.

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 coverage is 100% and the schema already describes the single optional filter, so the baseline is 3. The description does add a richer value list (equity | crypto_equity | etf | index | commodity | fx | rates | preipo), but that list does not match the schema's own description ('stocks | indices | commodities | forex'), leaving the agent unsure which vocabulary the filter actually accepts.

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?

Names the exact resource (tokenized stocks, ETFs, indices, commodities, FX, rates, pre-IPO names traded as PERPs on Lighter/Hyperliquid builder markets) and the output granularity ('one row per underlying ... with every venue's mark, open interest, 24 h volume, funding APR and the price gap between venues in bps'). It also explicitly separates itself from the sibling get_hl_builder_markets, which returns the raw HIP-3 per-dex list.

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?

Gives an explicit alternative for the raw-venue-list case ('use get_hl_builder_markets for the raw Hyperliquid HIP-3 list by dex'), which is actionable routing guidance. It offers no guidance on when to prefer this over the sibling get_stocks, and no exclusions such as coverage limits or which venues are included.

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