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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds what the payload actually contains — breadth, buying pressure, momentum, unusual activity, data freshness — which is meaningful since no output schema exists.

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?

Two sentences, zero filler, and the content summary is front-loaded ahead of the routing hint. Every clause carries information.

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 compensates by enumerating the returned dimensions and signaling data freshness. Combined with annotations covering the read-only/idempotent profile and the routing to market.opportunities, an agent has everything needed to call it 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% and the single window parameter is fully documented in the schema, including its enum and default. The description adds no syntax or interpretation guidance for window, so baseline 3 applies.

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?

States a specific verb ("Get") and a concrete resource set: market-wide breadth, buying pressure, momentum, unusual activity and data freshness. It names the sibling it is not (market.opportunities), so an agent can separate the two without opening either schema.

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?

"Use for breadth, regime and the top movers in one call" gives an explicit when-to-use, and "for a goal-driven scan use market.opportunities" names the alternative with the condition that selects it. It stops short of stating exclusions (e.g., single-symbol or historical use cases).

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