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

Annotations only declare readOnlyHint=true; the description adds two behavioral facts the agent needs: results are paginated and access requires a premium account. That is real context beyond structured fields, though it doesn't say what happens on a non-premium call (error vs. truncated results).

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 short sentences, no filler, with the core purpose front-loaded. Every sentence carries a distinct fact (what it returns, pagination, access tier).

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 list tool with a fully documented two-parameter schema and no output schema, this covers purpose, pagination, and the premium constraint. It stops just short of stating the return shape or the cost of large offsets, which matters at a 1000 max limit.

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 both parameters (limit, offset) are fully documented in the schema, including bounds and defaults. The description's mention of pagination is consistent but adds no syntax or semantics beyond what the schema already supplies, so the baseline 3 applies.

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?

The description states a specific verb and resource: returns a list of available companies with ticker symbols. That is distinguishable from siblings like getCurrentStockPrice or getStockExchange, though it never explicitly contrasts itself with searchTickers or getTicker, which retrieve overlapping ticker data.

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?

No when-to-use guidance is given. With siblings such as searchTickers, getTicker, and getAllStockExchanges in the same namespace, the description should say when to enumerate the full list versus searching for a specific ticker. 'Premium only' is an access prerequisite, not usage guidance.

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