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

Annotations already supply readOnlyHint, idempotentHint, and non-destructive status. The description adds valuable context: today's snapshot semantics, consecutive-day tracking, and a factual-only/no-recommendations stance.

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?

The description front-loads the most important information: what the tool returns, followed by input requirement and caveats. The final disclaimer about MarketPing's policies is slightly redundant after 'never a rating' but still reinforces intended use.

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, the description enumerates the core return fields and input expectation well. It omits ordering or edge-case behavior, but those are not critical for a simple read-only lookup.

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% for both parameters, so the baseline is 3. The description adds meaning for the stack parameter by specifying it must come from list_stacks, which is useful provenance beyond 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?

The description clearly states the resource (companies in one stack) and the returned fields, distinguishing it from list_stacks and stack_changes. It lacks an explicit verb like 'returns' or 'fetches', but the meaning is unambiguous.

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?

It gives clear usage context: fetch a slug from list_stacks first, and treat membership as a fact about screens cleared today, not a rating. It does not explicitly name alternatives or when-not-to-use, but the boundaries are clear enough.

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