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

Annotations already declare readOnlyHint=true, so safety needs no restating; the description instead adds genuinely new behavior: output is `results` in input order plus an `unresolved` bucket for unknown or no-price-history tickers, and the server resolves names rather than requiring exact symbols. It does not discuss rate limits, cost of a 50-ticker call, or partial-failure semantics beyond `unresolved`.

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 clauses: the capability and cap first, the use case in parentheses, then the return shape and date-parameter pointer. No filler and the most decision-relevant facts (batch limit, one call, output buckets) are front-loaded.

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 5-parameter read tool with no output schema, the description covers the inputs it must clarify (ticker cap, name resolution, date params by reference) and describes both return buckets. It is slightly thin on `chart_range`, whose side effect of injecting a `chart` payload into the first five results goes unmentioned, relying on the schema alone.

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 schema already documents every parameter including `context`, `tickers` cap of 50, and `chart_range`. The description adds only the ordering guarantee of `results` and the 'same as stock_prices' equivalence for `to`/`from_`, which is useful but marginal against a fully documented 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?

States a specific verb-like action (fetch the same digested price context) for a specific resource (up to 50 tickers in one call) and frames the canonical use case (watchlist / cohort snapshot). It also cross-references the sibling tool `stock_prices` and explicitly scopes itself to batch/cohort work, so an agent can pick it over `stock_prices` or `price_series` without opening a 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 clear usage context ('watchlist / cohort snapshot', 'which of these names are most extended, or deepest in drawdown') and implicitly routes single-ticker work to `stock_prices` via the 'to/from_ as in stock_prices' note. It does not state explicit exclusions (e.g. when a full series or screening tool would be better), so it lands just short of a 5.

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