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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the read-only nature is covered. The description adds genuinely useful pagination behavior (200 per page, cursor-driven continuation), but says nothing about error behavior for invalid block names or what happens at the end of a block.

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, front-loading what is returned (ordered block characters) before how to continue (cursor). Every clause earns its place with no filler.

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?

For a two-param read-only list tool with no output schema, the ordering, page size, and continuation mechanism are all disclosed. Only the shape of a returned character entry is left unspecified, which is minor given the absent output schema.

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 both parameters are documented in the schema (block name example, cursor provenance). The description reinforces the cursor's continuance role but adds no syntax or format detail beyond what the schema already provides; 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 (a Unicode block's characters) with ordering and batching scope. It is distinguishable from get_character (single char), list_blocks (blocks, not chars), and search_characters (query-driven), though it never names those siblings explicitly.

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 is only implied: the schema's block param points to list_blocks for naming, and the description explains how to continue with the cursor. No when-to-use vs. search_characters guidance or exclusions are stated in the description itself.

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