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

Annotations already cover read-only and open-world behavior, but the description adds two things they cannot: the required 'mcp:portfolio' scope (an auth prerequisite the agent must know) and the freshness guarantee 'Real financial data - never cached'. It does not disclose pagination or result shape, which is a minor remaining gap.

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?

Three tight fragments: purpose first, then the scope prerequisite, then the view taxonomy and the freshness note. Nothing is repeated from the schema or annotations and there is no filler.

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 read-only, 2-parameter tool with no output schema, the definition covers auth scope, all view semantics, and data freshness, which is enough to invoke it correctly. The undocumented `limit` (default 50, max 50) is the one 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 description coverage is 0%, so the description carries the burden and does explain every `view` enum member with a concrete meaning, adding real value over the bare enum list. The `limit` parameter is never mentioned, so it only partially compensates for the coverage gap.

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+resource ('Get the authenticated user's own portfolio') and immediately distinguishes it from every sibling, which all deal with third-party companies, insiders, filings, or market data rather than the caller's own account. No ambiguity about what is returned.

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?

It maps each `view` value to a concrete use case (account totals, current positions, daily P&L, trade journal), which tells the agent which invocation fits which intent. It stops short of naming when NOT to use it or pointing at an alternative tool, but no sibling overlaps this resource.

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