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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered; the description adds genuinely new behavior: per-call pricing ($0.003, 10 free/day, x402 payment listing), and error semantics (isError on invalid input/upstream failure and that errors are not charged). These are concrete traits an agent needs and cannot get from the schema.

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?

Front-loaded with what it returns, then scoping alternatives, then cost and error handling. The dense semicolon-separated phrasing packs high information value with no filler sentences.

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 single-param read tool with an output schema and full annotation coverage, this description supplies everything else an agent needs: scope, alternatives, cost, and failure behavior. Nothing material is missing.

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% and there is a single required parameter whose pattern and format (base58, 64-90 chars) are fully documented in the schema. The description confirms the input is a Solana signature but adds no syntax or format detail beyond the schema, so 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?

Opens with a specific verb+resource ('Turns any Solana transaction signature into plain facts') and enumerates the concrete outputs (status, fee, programs, balance changes, summary). It also names the type of transactions covered (swaps, pump.fun trades, LP moves, transfers, failures), making it unmistakable against siblings.

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 'When to use: For Solana signatures; for 0x hashes use evm_tx', giving both the condition and the named alternative. Nothing about tool selection is left to inference.

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