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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful context beyond that: the account is derived from the session cookie in the MCP request rather than an input identifier, and it clarifies that the account is global with no per-product activation. It still says nothing about what the counters/identity actually contain or their freshness.

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 compact sentences with no padding; the core identification of the resource comes first. The second sentence is arguably tangential framing, but it is short and pre-empts a plausible agent question about product activation.

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, the description carries the burden of explaining what comes back, and it only gestures at 'identity and private counters' without naming the fields or shape. For a zero-required-parameter read tool the gap is moderate, not fatal, but an agent cannot anticipate the response.

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%, so the single optional 'locais' parameter (comma-separated document IDs, 90 max, 1529 chars) is fully documented in the schema. The description mentions no parameters at all, adding nothing about the filter's role or how results change when it is supplied, which is the baseline-3 case.

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?

The description identifies the resource ('the identity and the private counters of the account session') but uses a noun phrase rather than a clear verb+resource statement, and never says outright that the tool retrieves/returns that data. It also does not distinguish itself from nearby siblings such as account_tracking or my_documents, so an agent must infer the boundary.

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 statement of when to call this tool, what prerequisites exist, or which sibling to prefer for related account data. The only guidance-like sentence ('there is no activation per product') addresses a domain concept rather than tool selection.

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