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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description goes beyond them by disclosing data provenance ('read from our own monerod') and the domain-specific behavior that Monero blocks are never full, so the baseline tier normally confirms next block — useful context an agent could not derive from structured fields.

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 the core purpose, then structured into When to use / Do not use / Returns blocks. Every sentence carries information — the alternatives, the return fields, and the fee-market caveat all earn their place.

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 compensates by enumerating the return fields (baseline_fee_per_kb_xmr plus priority_tiers[] with priority, fee_per_kb_atomic, fee_per_kb_xmr). Combined with the usage routing and provenance note, an agent has everything needed to call and interpret this 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?

The tool takes no parameters, so there is nothing for the description to clarify at the parameter level; the baseline for a zero-parameter tool applies. The description instead spends its budget on the return shape, which is appropriate.

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 ('Monero fee estimate per kB') and adds the structural detail that it is split into ascending priority tiers read from the operator's own monerod. This cleanly distinguishes it from btc_get_fee_rates and eth_get_fee_rates by naming the chain in the purpose itself.

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 explicit when-to-use triggers (pricing an XMR transaction, deciding whether to pay the baseline fee for next-block inclusion) and explicit do-not-use cases naming the two nearest alternatives (btc_get_fee_rates, xmr_get_mempool_state). Nothing 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.