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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds real value by disclosing the return shape (daily time series) and the portfolio scope, which matters since there is no output schema. It says nothing about defaults when dates are omitted, data granularity limits, or what 'performance' is denominated in.

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 front-loaded sentence that identifies verb, resource, cadence, and scope with zero filler. Nothing needs to be cut.

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 three optional parameters, no output schema, and rich annotations, the definition is serviceable but thin: it leaves the roi_mode semantics, the effect of omitting both dates, and the unit of 'performance' unexplained. An agent can call it, but cannot predict the result precisely.

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%, so the baseline is 3. The description adds no meaning beyond the schema, and notably ignores roi_mode — the one enum parameter whose 'original' vs 'delay-adjusted' distinction is genuinely non-obvious and would benefit from explanation.

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 (get) and resource (daily performance time series) with a precise scope: the defense sector portfolio held by Congress. This clearly separates it from get_defense_holdings (holdings, not performance) and get_trump_admin_performance / get_trump_performance (different portfolio owner), though it never names those siblings explicitly.

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?

The scope statement implies when the tool applies (Congress-held defense positions), and the 'performance' vs 'holdings' split implicitly routes against get_defense_holdings. But there is no explicit when-to-use, no mention of alternatives, and no note about the zero-required-parameter default behavior.

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