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

Annotations already mark this as read-only, idempotent, and non-destructive, and the description adds substantial behavioral context: it reads the NearBlocks indexer, costs $0.02 per call on x402, supports pre-paid credit headers, and requires no wallet or API key. This gives an agent a complete picture of side effects, dependencies, and cost without contradicting the 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 longer than average, but nearly every sentence adds new information: output contents, data source, limit default, required input, and pricing model. It is front-loaded with the purpose and then provides operational details. The only minor inefficiency is the conversational opener followed by a dash, which is acceptable for readability.

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 and both parameters already documented, the description fills the remaining gaps: it specifies the data source, cost, auth requirements, default limit, and required parameter. An agent has everything needed to invoke this tool correctly and interpret its behavior, and no important context is missing.

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 coverage is 100% (both account and limit have descriptions), so the baseline is 3. The description adds value beyond the schema by stating the default limit (25) and reinforcing that account is required, plus clarifying that limit controls 'how many recent transactions' to read. This is a meaningful increment over the bare schema.

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 opens with a clear purpose: 'Recent history of a NEAR account, summed up', then enumerates specific outputs such as transactions signed/received, failures, NEAR sent/received, token flows, most-called contracts, and activity signals. This level of detail lets an agent distinguish it from siblings like near_portfolio or wallet_activity without inspecting those tools.

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 clear operational context: required input (account), how limit affects results (default 25), the data source (NearBlocks indexer), and usage constraints like pricing and free-tier availability. However, it does not explicitly state when to choose this tool over alternatives (e.g., near_account or generic wallet_activity), so it stops short of full when/when-not guidance.

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