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

Annotations already provide readOnlyHint, openWorldHint, and idempotentHint, indicating a safe read operation. The description adds concrete behavioral context: the source endpoint, the specific RPC methods used, and the 30-second cache TTL, which helps the agent understand data freshness and provenance.

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 two sentences, each carrying essential information: the first lists all returned metrics, the second gives source, cache behavior, and usage context. It's front-loaded with the main action and contains no extraneous words.

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 simple parameterless read-only tool, the description covers what data is returned, the source, the cache behavior, and when to use it. All relevant details are included, and while there is no output schema, the description explicitly lists the fields, making it self-sufficient.

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?

There are zero parameters, so no schema semantics are needed. Per the rubric, a zero-parameter tool receives a baseline of 4. The description adds value by listing the output metrics even though it doesn't discuss parameter syntax.

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 specifies the exact resource (Solana mainnet network metrics) and enumerates the specific data points returned (TPS, average TPS, slot, slot time, epoch progress). This clearly distinguishes it from sibling crypto tools like tf_btc_price or tf_crypto_movers, which focus on prices rather than network throughput.

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?

Explicitly states the intended use case: 'Use when the agent needs to assess Solana network throughput or congestion.' This is clear context, but it doesn't mention when not to use it or name alternatives; however, given no sibling tool provides Solana network metrics, the implied sole purpose is sufficiently clear.

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