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

With no annotations, the description carries full burden. It discloses the type of data returned (price, TVL, protocol count, chain status), indicating a read-only aggregate snapshot. However, it doesn't specify data freshness or any limitations, but for a simple overview this is adequate.

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 a single, front-loaded sentence that immediately states the tool's purpose and then lists four concrete outputs. Every word earns its place with no redundancy.

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 its zero-parameter input and no output schema, the description fully explains what the tool provides. For a simple overview endpoint, this is complete and actionable.

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 tool has zero parameters, so the description doesn't need to explain parameter details. The schema is empty, and the description adds contextual value by naming the specific data dimensions covered, which is more than a baseline for no-parameter tools.

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 uses a specific verb ('overview') tied to a clear resource ('Arbitrum ecosystem') and lists concrete data points (ARB price, TVL, protocol count, chain status). This distinguishes it from the more specialized sibling tools like arb_defi_yields or arb_gas_tracker.

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 implies generic usage as a broad overview, but it doesn't explicitly state when to use this tool versus the many specific siblings. No alternatives or exclusions are mentioned, leaving the agent to infer that this is the 'big picture' tool.

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