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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), but the description adds substantial non-structured behavior: not_found is a charged 200, malformed input is an uncharged 422, RPC failure is an uncharged 503, typical latency 0.3-2 s, price and free-tier quota. The prompt-injection warning about returned page text is a genuine operational caveat absent 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?

Purpose and the sibling alternative are front-loaded, then error/pricing/security facts follow. It is dense and reads as a spec block rather than prose, but every sentence carries distinct decision-relevant information and none is padding.

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 present, return shape need not be described; instead the description covers the gaps that matter for a paid, metered RPC read: error taxonomy, charging rules, network/commitment, latency, price, and quota. Nothing an agent needs to call this correctly 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 the single signature parameter is fully documented in the schema (base58, 87-88 chars, pattern). The description adds no format or constraint detail beyond what the schema already carries, so the 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?

States a specific verb and resource ('Get a parsed Solana transaction by its signature') and immediately names the sibling it is not: 'For an address's recent signatures use get_solana_signatures.' An agent can distinguish this from get_solana_signatures, get_transaction, and get_solana_account without opening a schema.

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?

Explicit routing guidance to the alternative tool and the condition that selects it (address-level history vs. single signature). It also specifies the operating envelope — Solana mainnet, confirmed commitment — which tells the agent when results are valid.

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