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

Annotations already declare readOnly/openWorld=false/destructive=false, but the description adds substantial beyond-schema behavior: signed quantities, owner per-share costs never split-restated, per-listing vs portfolio currency with official rates, every mark naming its session, unpriceable/expired positions having unknown (not zero) value, watched instruments not counting as exposure, and lot ids addressing update/close/remove tools.

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-loads purpose and the core omit/pass usage before the denser return-semantics details. It is long and information-dense, but each sentence conveys distinct, non-redundant behavior (signed quantities, currency, marks, unpriceable positions, watched instruments, lot ids), so little is wasted.

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 a rich return surface (lots, cost basis, profit, watched instruments), the description carries the burden well by explaining currency, marks, and valuation semantics. It stops short of describing the overall response structure or pagination, but covers what an agent needs to interpret results 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?

Schema coverage is 100%, so baseline is 3, but the description adds real meaning beyond the schema: omit-to-list behavior, the single-portfolio full-return case, and the 'Name (Creator)' disambiguation for shared portfolios whose name is taken. It leaves minor format/syntax details to the 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 (Get) and resource (caller's saved portfolios, plus organization-shared ones) and enumerates the content returned: lots, cost basis, realized and unrealized profit, watched instruments. It explicitly distinguishes itself from GetInstitutionPortfolio for 13F holdings, so an agent can route without opening either schema.

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?

Gives explicit conditional usage: omit 'portfolio' to list all, pass a name to select one, with the edge case that a single portfolio is returned in full. It names the alternative tool (GetInstitutionPortfolio) and the condition that selects it, leaving nothing to inference.

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