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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered structurally. The description adds useful context about what live state is surfaced (login status, sequence numbers, connection details), but says nothing about auth requirements (apiKey), error behavior for unknown sessions, or freshness of the 'live' data.

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?

A single front-loaded sentence with no filler; the parenthetical efficiently enumerates the returned state. It is appropriately sized for a simple read tool, though it is arguably terse for the param gaps it leaves.

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, and the description partially compensates by naming the state fields returned. However, for a tool with two required parameters at 33% schema coverage, the definition leaves identity/lookup semantics (what 'instance' means, whether apiKey is needed) unexplained.

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 33%, so the description should compensate for undocumented parameters but does not. It gives no meaning for 'instance' or 'apiKey' (both absent from schema descriptions), and the only documented param, 'session', is already explained in the schema as coming from fixsim_list_sessions.

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 ('Get') and resource ('one FIX session's settings and live state') and enumerates the returned facets (login status, sequence numbers, connection details). The singular 'one ... session' implicitly contrasts with the sibling fixsim_list_sessions, though no sibling is named explicitly.

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?

There is no explicit when-to-use or when-not-to-use guidance and no alternatives are named. The agent must infer from the name that this is the single-session inspection call versus the list variants; nothing in the text routes it.

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