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

Annotations already indicate readOnly, openWorld, idempotent, and non-destructive behavior. The description adds significant behavioral context beyond this: parallel venue queries, error venues reported as { reachable: false }, never failing the call, return shape details, divergence only computed with Jaccard overlap, and honest caveat that high spread does not mean real arbitrage.

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 longer than average, but it is well-structured, front-loaded with the core purpose, and uses clear sections (landscape scan, return shape, HONESTY caveat, alternative). Every sentence adds value, though it could be slightly more concise for faster scanning.

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 no output schema, the description takes on full responsibility for explaining return values and behavior. It covers the return shape, failure handling, divergence logic, and important caveats about interpreting spreads. This is complete enough for an agent to select 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?

The schema has 100% coverage for both parameters, so the baseline is 3. The description does not add much parameter-specific detail beyond the schema; it indirectly references per-venue top matches and the topic concept, but the schema already fully documents `topic` and `per_venue`. No additional semantic value beyond what the schema provides.

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 states a specific verb and resource: it is a 'Cross-venue prediction-market LANDSCAPE scanner' that 'show[s] how 5 venues are pricing [a topic] side by side and flag[s] divergence.' It clearly distinguishes itself from executable arbitrage tools by naming the alternative and explicitly stating it is 'NOT an executable-arb tool.'

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 context: use for scanning one topic across multiple venues to find where to look for mispricing. It also states when not to use it ('NOT an executable-arb tool') and names the alternative (`polymarket_arbitrage` pack) for executable arbitrage requiring order-book depth.

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