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

Annotations only tell the agent it is non-destructive but not read-only; the description adds the substantive behavioral facts that no funds are moved and that payment requires separate authority plus a compatible signing wallet. That is real context beyond the annotations, though it omits what artifact is produced and any idempotency/side-effect detail.

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 short sentences, front-loaded with the core purpose, and the safety caveat follows immediately. Nothing is padded, though the phrasing is terse enough to be slightly cryptic about the output.

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 one-parameter tool with no output schema, the definition covers the key safety boundary but leaves notable gaps: it never describes what the quote/invoice result contains, whether package_id may be omitted, or what the enum choices mean. Annotations cover the safety profile, so the missing pieces are moderate rather than severe.

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 0% for the single package_id parameter, so the description must carry the load. Its phrase 'prepaid package or current custom option' loosely gestures at the parameter, but the enum values (dawn, orbit, solar) and the fact that package_id is optional (required is empty) are never explained.

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 states a specific action and object ('Quote a prepaid package or current custom option'), which is clearer than the bare name eclypse_create_invoice and clarifies that 'create' here produces a quote, not a payment. It does not, however, distinguish itself from any named sibling such as eclypse_catalog, so the agent must infer the boundary.

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?

It draws a useful boundary by stating 'Does not send money or debit a wallet' and that paying needs separate operator authority and a signing wallet, which tells the agent this is a pre-payment quoting step. However, it names no alternative tool for the payment step and gives no explicit 'use this when...' trigger.

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