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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description nevertheless adds real value beyond them: no fuel cost, ship does not move, and the return is a sector list to warp along yourself. Solid but the remaining gaps (error cases, cost of planning) are minor against full annotation coverage.

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?

Four short, front-loaded sentences with zero filler; the negative framing ('not fly', 'NOT autopilot') appears immediately, then usage, then the read-only guarantee.

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?

No output schema exists, yet the description explains what comes back (a sector list, plus a faster hyperlane variant when available) and confirms the call is side-effect free. That is everything needed to invoke and interpret the result 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 description coverage is 100%, so both bearer and dest_sector_id are already documented in the schema. The description adds no syntax or format detail beyond what the schema states, 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 ('Plan ... the fastest route to a distant sector') and preemptively disambiguates from near-siblings: 'not fly', 'NOT autopilot', warp hop-by-hop. An agent can distinguish it from warp and jump_hyperlane without opening any 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?

Gives an explicit trigger condition — 'Use this whenever your destination is not a direct neighbour (warp fails with NO_ROUTE)' — and names the alternative it relates to (warp). Both when-to-use and the failure mode that forces it are specified.

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