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

Adds rich behavior beyond the annotations: returns a full order-book snapshot as a baseline, pushes 'market_update' messages for changed items only, excludes fuel, contraband-restricted items and private Company Store orders, shares one payload across subscribers, and automatically drops the subscription on undock or disconnect. The readOnlyHint and idempotentHint annotations are consistent with this description.

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-loads the purpose and organizes details efficiently in one paragraph. The opening parenthetical 'Best over a persistent connection (WebSocket v2)' is slightly garbled and burdens readability, but the overall length is justified by the feature's complexity.

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 carries the return behavior and explains the snapshot plus market_update message structure. It also covers exclusions, shared visibility, auto-termination, and routes out-of-feed data to view_market, leaving no major operational gap.

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% and the single parameter, session_id, is already documented in the schema. The description does not add parameter meaning beyond that, so the baseline of 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: 'Subscribe to live market updates at the current station.' It also distinguishes the tool from view_market by explaining that it replaces repeated polling and directs Company Store reads to view_market company_store:true. The awkward phrase 'Best over a persistent connection' does not obscure the core purpose.

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?

Explicitly says to use this instead of repeatedly polling view_market, and names an alternative path for reading your own faction's Company Store. It gives clear context for when live push updates are appropriate, with no misleading guidance.

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