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

Goes well beyond the annotations by disclosing append-only semantics, the exact trigger conditions for a new entry (import_portfolio only when holdings/assets actually change, plus each restore), the dedup rule for identical resubmissions, and precisely what is and is not captured. These are behavioral facts the readOnly/idempotent hints cannot convey.

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 sentences, front-loaded with the core definition before the trigger rules and the recovery hint. Information density is high, though the parenthetical about valuations being recomputed is slightly tangential and the sentences are long.

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?

An output schema exists, so return values need not be described; the description instead covers everything else an agent needs — snapshot contents, creation triggers, dedup behavior, and the undo path. Nothing material is missing for correct invocation.

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 100% and the single 'limit' parameter (min 1, max 100, default 20, most recent first) is fully documented in the schema. The description adds no parameter-level detail, which is acceptable here but earns only the baseline.

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 (list) and resource (append-only portfolio snapshots) and immediately defines what a snapshot is: whole-portfolio quantities, average prices, symbols and asset classes at a moment in time. It also distinguishes itself from computed data by noting market prices/valuations are never stored, which separates it from get_portfolio/analyze-style siblings.

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?

Explicitly says when to use it ('to see when the portfolio changed') and names the follow-on action restore_portfolio_snapshot for undoing a bad import. It does not, however, state when NOT to use it — e.g. that get_portfolio should be used for current holdings — so the routing against the closest sibling is left implicit.

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