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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds real value by disclosing the return content (block detail plus canonical vs orphan status), but says nothing about not-found behavior, chain context, or response size for what is an open-world lookup.

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 sentences with zero waste: the lookup modes and scope come first, the return value second. Nothing is repeated from the schema verbatim beyond the necessary format constraint.

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 one-parameter read-only lookup with no output schema, the description covers input forms, scope, and the salient return signal. What is missing is error/not-found behavior and any hint of what 'block detail' contains, which is minor given the tool's simplicity.

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% and the single parameter already documents the number-or-64-char-hex format. The description only reinforces the length and adds the valid height range (0 to chain tip), so the baseline of 3 applies with minimal added meaning.

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 names a specific verb (Find) and resource (block), and specifies the two accepted query forms and the full chain scope down to genesis. It does not, however, distinguish itself from the sibling get_block, so an agent cannot tell from this text alone why both exist.

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: 'anywhere in the chain down to the genesis block' plus the canonical/orphan return value hints this is for arbitrary or potentially non-canonical block lookups. There is no explicit when-to-use statement and no exclusion pointing at get_block, recent_orphans, or chain_provenance for the adjacent cases.

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