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

With no annotations provided, the description carries the full behavioral burden. It explicitly warns that unanswerable fields are null, not empty, and that positions_listed is null when marketplace listings aren't indexed — crucial to avoid misinterpretation. It also clarifies the output is counts, not depth, managing expectations. It doesn't discuss side effects or access requirements, but for a read-only query tool this is solid.

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?

The description is fairly compact and front-loads the core idea before giving specifics and a null-handling warning. The opening question is slightly rhetorical, but every sentence contributes information. No repetition or 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?

The description lists the concrete return components (best bid, time remaining, 24h closers, counts, outstanding, collateral, distinct lenders/borrowers over 30 days) and handles the null/empty-edge case. The optional filtering by pair/network is covered in the schema. Missing an explicit tie to sibling tools, but overall the tool is fully callable with the provided information.

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%: the schema already gives detailed descriptions for pair and network, including the testnet caveat. The description adds nothing about parameters, so baseline 3 is appropriate.

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 opens with 'What is open right now — auctions, bids and positions listed?' and then enumerates the returned data: open auctions with best bid and time remaining, those closing within 24 hours, plus aggregate totals. This clearly identifies the tool as an open-book/current-state snapshot. It stops short of explicitly naming sibling tools it differs from, so not a full 5.

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?

The description states that output is 'counts rather than a characterisation of depth,' indicating it's for aggregate book data, but it never tells the agent when to prefer get_book over siblings like get_user_positions or find_auctions_matching_criteria. There's no explicit when-to-use or alternative routing, so usage must be inferred.

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