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

With no annotations, the description carries the full burden and does disclose the substantive traits: the return is capped at 30 levels a side, includes a midpoint, and requires no API key. It leaves out whether the book is a live snapshot or delayed, and what happens on an unknown market.

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 front-loaded sentence: resource first, then depth cap, then midpoint, then the auth note. No filler or redundancy.

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 two-parameter read tool with full schema coverage and no output schema, the description supplies the return-shape essentials (levels per side, midpoint) plus the auth note. Only minor gaps remain around freshness and error behavior.

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 both parameters are already documented, and the description only implies single-market scoping. 'No key needed' loosely reinforces that key is conditional, but adds nothing the schema does not already state.

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 a specific resource — one market's order book — plus its scope (a single market, up to 30 levels per side) and contents (midpoint). That is enough to separate it from get_prices and list_markets without opening a schema, though it does not explicitly name those 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?

Usage is only implied: an agent can infer this is the depth/snapshot call for one market, versus list_markets for discovery. There is no explicit 'use when' condition or exclusion against get_prices, and no guidance on invalid market ids.

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