whoamiThe signed-in account (name, email, currency, business details printed on invoices) and what this token may do (read or write). Call this first to confirm the connection.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| name | Yes | ||
| Yes | |||
| business | Yes | ||
| currency | Yes | ISO 4217 code every amount is in, e.g. USD or EUR | |
| member_since | Yes | ISO time the account was made | |
| token_access | Yes | What this token may do |
Changes observed during successful MCP inspections.
Output schema / properties / currencyAdded value: +{
+ "description": "ISO 4217 code every amount is in, e.g. USD or EUR",
+ "type": "string"
+}Output schema / requiredPrevious value: -[
- "id",
- "name",
- "email",
- "member_since",
- "token_access",
- "business"
-]New value: +[
+ "id",
+ "name",
+ "email",
+ "member_since",
+ "token_access",
+ "currency",
+ "business"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and a closed world, so the safety profile is covered. The description still adds real value beyond them by disclosing what the call reports back — account identity plus the token's permission level — which tells the agent this is a preflight/authorization probe.
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 sentence, front-loaded with the returned identity data, with the call-to-action appended at the end. No filler and nothing redundant with the annotations.
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 parameters, rich annotations, and an output schema present (so return shapes need not be explained), the description supplies exactly the missing piece: what the tool tells you and when to reach for it. Nothing an agent needs to invoke it correctly is absent.
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; there is nothing for the description to disambiguate and it correctly does not invent parameter details.
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, concrete output: the signed-in account's identity fields (name, email, currency, invoice business details) plus the token's read/write capability. No sibling tool in this list does identity/authorization introspection, so it is cleanly distinguishable.
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?
"Call this first to confirm the connection" gives explicit ordering guidance and a clear trigger condition. It does not name a when-not case or an alternative, but no realistic alternative exists for this capability.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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