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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with 'Changes nothing' while adding value the annotations cannot: the docking prerequisite and the fact that the quote is time-sensitive ('RIGHT NOW') and includes the caller's own price impact. It could go further on rate limits or quote staleness, but the added context is substantive.

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?

One front-loaded sentence establishing the dry-run framing, followed by two clipped fragments for the no-side-effects guarantee and the docking prerequisite. Dense but every clause adds information an agent needs.

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?

There is no output schema, and the description compensates by enumerating precisely what the estimate returns (unit price with price impact, tax, total, affordability, cargo fit, stock level). Combined with the stated prerequisite, an agent has everything needed to call this correctly.

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 coverage is 100%, so the schema already documents item_code, quantity, and bearer. The description restates 'item_code x quantity' and frames quantity as intended purchase size, but adds no format or constraint detail beyond the schema. Baseline 3 applies when the schema carries the load.

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 ('Dry-run for buy: shows what buying item_code x quantity would cost') and enumerates exactly what is computed: unit price including own price impact, buy tax, total, affordability, cargo fit, and station stock. This clearly separates it from the sibling 'buy' tool, which would perform the transaction rather than simulate 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?

'Dry-run for buy' plus 'Changes nothing' makes the use case obvious: call this before committing to a purchase. The prerequisite 'Ship must be docked' is stated. It stops short of explicitly naming 'buy' as the alternative or stating when not to use it, but the routing signal is strong.

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