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

Annotations (readOnlyHint:true, openWorldHint:true, idempotentHint:true, destructiveHint:false) indicate safe, non-destructive, possibly varying results. The description complements this by detailing exactly what the tool does: walks the CLOB order-book ladder, returns top_of_book, vwap_fill_price, slippage, and a verdict (clean|degraded|cannot_fill). It also warns about forced_directional_risk, disclosing the key behavioral trait: partial fills can strand the user unhedged. No contradictions with annotations.

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 well-structured with clear sections (SINGLE-MARKET, BASKET) and a usage note at the end. However, it is somewhat lengthy (three paragraphs) and includes some redundancy (e.g., repeating default values mentioned in the schema). While every sentence adds information, a more concise version could improve readability without losing content.

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?

Given the tool's complexity (two modes, multiple return fields) and the absence of an output schema, the description is comprehensive. It details all return fields for both modes, explains the verdict categories, specifies the forced_directional_risk, and provides constraints (max clean notional). This fully equips an agent to understand and invoke the tool correctly.

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 four parameters described). The description adds meaningful context beyond the schema: clarifies that size_usd default 1000 means max spend on buys and target proceeds on sells for single-market, and settlement notional for basket; explains side defaults (auto from partition sum for basket); and describes that market and event are mutually exclusive modes. This adds significant value, justifying a 4.

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 clearly states the tool's purpose: 'Realizable-vs-theoretical edge check against live CLOB order-book depth.' It distinguishes between single-market and basket modes, explaining what each does, and explicitly positions itself as a prerequisite check for arbitrage and edge trades, differentiating it from sibling tools like polymarket_arbitrage and polymarket_edges.

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 provides explicit usage guidance: 'USE THIS before acting on any polymarket_arbitrage SELL/BUY-EVERY-LEG signal or any polymarket_edges trade above ~$500.' It explains when not to use it (when theoretical overround may not be capturable) and the risk of partial basket fills converting an arb into an unhedged directional position, offering clear context for when this tool should be consulted.

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