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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds return-content context — that the result includes the raw FIX message and an audit trail — which is meaningful behavioral information given there is no output schema.

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?

Two sentences, zero filler, with the core action and identifier front-loaded and the use case immediately following. Every clause earns its place.

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?

The read-only/idempotent annotations cover safety and the description covers purpose plus return contents, so the read path is adequately explained. However, with two required identifying parameters (instance, session) entirely undocumented, the definition leaves a real gap for a tool that requires them to be called successfully.

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 only 25%: clOrdId is documented in both schema and description (tag 11), but the required instance and session parameters plus apiKey have no description in either place. The description does not compensate for this gap at all, so an agent has no guidance on what instance/session should contain.

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 ('Get one inbound order by ClOrdID') and the singular 'one' implicitly distinguishes it from the plural sibling tools like fixsim_list_orders_in. It is clear enough to act on without opening the schema, though it never names an alternative to contrast against.

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?

The second sentence gives a concrete use case ('explain why an order was rejected or what state it is in'), which is far more than most definitions offer. It stops short of stating when NOT to use it or naming the list siblings as alternatives for browsing.

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