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

With no annotations present, the description carries full responsibility for behavioral disclosure. 'List' strongly implies a read-only retrieval operation with no side effects, and 'most recent' implies ordering by recency. However, it does not state whether results are returned newest-first, what fields each block includes, or any other behavioral caveats.

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 clear, front-loaded sentence with no filler or repetition. It communicates everything it attempts to communicate in the minimum possible space.

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?

This is a simple, single-parameter list operation with a clear name and description. While it omits return-format details, the phrase 'list the most recent blocks' reasonably implies the output is the requested block list, and the schema fully covers the only input. The absence of annotations is a minor gap for such a straightforward read operation.

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 input schema fully documents the only parameter, `limit`, including its range and default value. The description adds no additional semantic detail beyond the schema, so the baseline score of 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?

The description states a specific verb ('List') and a clear resource ('the most recent blocks'), making the tool's basic purpose immediately understandable. It distinguishes itself from siblings like get_block (single block vs. list) and list_recent_transactions (blocks vs. transactions), though it does not explicitly name any alternative.

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?

Usage context is implied: an agent would use this when it needs recent blocks. However, there is no explicit guidance about when to prefer this over get_block or list_recent_transactions, nor any mention of exclusions or prerequisites.

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