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

Annotations already cover the safety profile (readOnly, idempotent, openWorld), yet the description adds real value: dual data provenance (explorer index vs on-chain, surfaced via `source`), pending-without-receipt semantics, and null-means-unreported. It omits error behavior (e.g., nonexistent hash) and any rate-limit/retry guidance, so not a 5.

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?

Three dense sentences, front-loaded with the core identity (one transaction by hash) followed by field list, then provenance/pending/null caveats. No filler and nothing repeated from annotations or schema.

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 no output schema, the description carries the return-value burden and does so — returned fields, `source`, `pending`, and null semantics are all covered. Missing only failure behaviour for an unknown hash, which is a minor gap for a two-param read tool.

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 50%: `chain` is documented in-schema via enum descriptions, `hash` is only constrained by a regex pattern. The description implies chain scope ('BNB Chain or Ethereum transaction by hash') and clarifies value units (wei), but adds little beyond what the schema already enforces, so baseline 3 is right.

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+resource (fetch one transaction by hash), the supported chains, and enumerates the returned fields. The sibling get_token is a different resource, and the description's scope ('transaction') makes the boundary obvious without needing to name it.

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?

Gives clear context for what the tool returns and explicitly declares a scope boundary ('Logs and decoded calls are not included'), which steers agents away from expecting receipts/logs. It never states when not to use it or names an alternative, so it stops short of a 5.

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