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

Beyond the readOnlyHint/idempotentHint annotations, the description discloses concrete return behavior an agent cannot infer from structured fields: it always returns an empty list, a count of 0, and a warning, and explains why (ship sensors only see your own POI). This is genuinely useful, though the explanation is tangled by nesting it inside the deprecation parenthetical.

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?

The DEPRECATED notice and alternative routing are correctly front-loaded, but the parenthetical restates the same content almost verbatim ('Use get_nearby... get_system...'), so roughly half the text is redundant. The core message survives, but the duplication is wasteful.

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 deprecated no-op tool, the definition is complete: it tells the agent the tool is useless, why, what it returns, and exactly where to go instead. No further context is needed to call it correctly (or, better, avoid it).

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?

There is a single required parameter (session_id) with 100% schema description coverage, so the schema fully documents it. The description adds no syntax or format detail about the parameter, which is the correct baseline when the schema already does the work.

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 exactly what this tool does ('always returns an empty agents list, count 0, and a warning') and explicitly flags it as DEPRECATED, immediately distinguishing it from functional siblings. It also names the two correct replacements, get_nearby and get_system, so the agent can route elsewhere 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?

It gives explicit when-not-to-use guidance ('DEPRECATED and going away') and names the precise alternatives with their use conditions ('get_nearby for the ships at your POI, and get_system with a ship scanner (sensor rating above 0) for ship counts at the other POIs'). 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.