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

With no annotations, the description carries the full burden and does disclose the return payload in detail (userId, emails, wallets on two chains, merchants with their fields), which is valuable given there is no output schema. It implies a read operation via 'Get' and mentions auth scoping, but does not state error behavior or whether the token is strictly required despite the schema calling it 'Optional'.

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 zero filler; scope and return contents are stated before any detail. Every clause contributes to selection or interpretation.

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 no-argument read tool with no output schema, enumerating the returned fields covers the essential gap. Missing only minor context such as auth failure behavior or whether the bearer token is mandatory, which is a small residual gap rather than a blocking omission.

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 100% and the single parameter (bearerToken) is already documented. The description still adds meaning by tying that token to account identity ('for the authenticated API key'), clarifying that the token selects whose profile is returned rather than being a generic optional auth header.

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 the profile') scoped explicitly to 'the authenticated API key' and enumerates the exact contents (userId, emails, wallets, merchants). No sibling tool in the list does anything comparable, so an agent can distinguish it immediately.

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 phrase 'for the authenticated API key' makes clear this is a self-scoped lookup with no target user argument, which is the main selection criterion. It does not name alternatives or exclusions, but none of the siblings overlap, so the context is sufficient.

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