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 valuable context beyond that: the payload includes the raw FIX message and audit trail, which tells the agent this is a forensic/diagnostic read.

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, and the resource/return payload is front-loaded before the usage guidance. 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?

For a single-record read tool with no output schema, the description tells the agent both what it returns (raw FIX message, audit trail) and why to call it. The one real gap is the undocumented instance/session parameters, which the agent must infer.

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 only 25% with 4 parameters, and two required parameters (instance, session) plus apiKey are undocumented in both schema and description. The description only restates clOrdId and its FIX tag, which the schema already provides, so it fails to compensate for the coverage gap.

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'), the lookup key (ClOrdID, tag 11), and the returned payload (raw FIX message and audit trail). The word 'one' implicitly distinguishes it from the sibling list_orders_in, though that sibling is not named.

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 a concrete when-to-use context: explaining why an order was rejected or determining its state. It does not name explicit alternatives (e.g., fixsim_list_orders_in for bulk review) or exclusions, so it stops short of full routing guidance.

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