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

Annotations already declare readOnly, idempotent, non-destructive and open-world behavior, so the safety profile is fully covered and the description carries a lower burden. The description adds nothing beyond them, however - no mention that results are a static platform-level list rather than per-user state, and no caveats about freshness.

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?

A single short sentence with the verb and resource front-loaded and zero filler. It is arguably too terse - one clause on what a chain entry represents (or that the list is static) would earn its place - but nothing is wasted.

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 documenting the return shape, full annotation coverage, and no parameters, this trivial enumeration tool needs little more than the statement given. The only gap is that the description does not indicate the list's scope or whether it should be cached, which is minor at this complexity.

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 takes zero parameters, so the baseline is 4; there is no parameter semantics for the description to explain. Nothing in the description misleads about inputs.

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 gives a specific verb ('List') and resource ('supported blockchain networks'), making it immediately clear this returns the set of chains the platform supports. No sibling covers the same resource, so no explicit differentiation is required, though it does not state scope details such as ordering or filtering.

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: an agent can infer this is the lookup to call before referencing a chain by name or ID, but the description never says when to use it or what to do with the result. No alternatives or exclusions are named, which is acceptable only because the resource is unique among siblings.

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