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

Annotations only cover read-only/non-destructive semantics; the description adds the real behavioral context: it requires an OAuth session, behaves differently on the keyless endpoint, and orders linked wallets with embedded ones first. The auth prerequisite and endpoint-specific fallback are exactly the traits annotations cannot convey.

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-loaded with what the tool returns, then the usage directive, then the auth caveat. It is dense and packed into essentially two long sentences with colons, which is efficient but slightly run-on compared with the cleanest definitions.

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 and only read-only annotations, the description carries the return-value burden itself and does so by enumerating the fields returned and their ordering. Auth requirements and the keyless-endpoint fallback round out everything an agent needs to call it correctly.

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?

The tool takes zero parameters, so the baseline is 4 and there is no input schema to compensate for. The description's field list pertains to outputs rather than inputs, which is acceptable given the empty schema.

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?

Names a specific verb/resource (retrieve the signed-in Epsilon account behind this session) and enumerates exactly what it returns: account id, handle, linked wallets, granted scopes, and connected client. This is clearly distinguishable from siblings like get_order, get_quote, or search_tokens, which deal with market data rather than session identity.

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 states when to call it ('Call it first after sign-in to learn the wallet address other tools need'), which makes it a prerequisite for other tool calls. It also documents the precondition (an OAuth session via /mcp/account) and the behavior on the keyless /mcp endpoint, where it explains how to sign in instead.

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