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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds 'page-based browsing', which is useful pagination context, but does not disclose return format or ranking behavior beyond what the schema and output schema already convey.

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 tight sentences with zero waste, front-loading the core action and following with the disambiguation. Every sentence earns its place.

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 an output schema present, return values need not be explained, and annotations carry the safety profile. The main residual gap is that the opaque 'metric' integer id (default 6) is never explained in the description, but otherwise the definition is complete for a simple two-param list tool.

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 the schema documents both 'page' and 'metric' itself. The description echoes the ranking-metric concept but adds no syntax or meaning for the metric id beyond what the schema states, so the 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 (List) and resource (top Google Finance stock instrument rows ranked by a selected metric), and explicitly differentiates from the sibling google_finance_markets_movers. An agent can distinguish it from the market-movers tool 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?

Names an alternative explicitly and the condition that selects it ('Use google_finance_markets_movers for the separate market-movers view'). Clear routing context, but no explicit when-to-use conditions for this tool beyond the contrast, so it falls short of a full 5.

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