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

With no annotations, the description carries the full behavioral burden. It does disclose the key pricing assumption — the cheapest paid monthly-equivalent tier, implying free tiers are excluded and annual figures are derived by multiplication — which is genuine value. It says nothing about unknown/unrecognized domains, partial results, or rate limits, which matter for a bulk pricing tool.

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?

Two short sentences, front-loaded with what is computed and the pricing rule, followed by the usage cue. No filler, though the second sentence is closer to a sales line than to an operational constraint.

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?

Output is described (monthly and yearly totals) and there is no output schema, so that gap is covered. For a simple one-parameter tool the definition is adequate, but the ambiguity between "tools" and the `domains` array plus unstated handling of unrecognized inputs leaves it short of complete.

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 0% for the single required parameter, so the description must compensate and largely does not: it says "set of tools" while the parameter is called `domains`, leaving unclear whether entries are domain strings (e.g. slack.com) or tool names. The maxItems=40 limit is also unexplained.

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 concrete action (compute total monthly and yearly cost) on a concrete resource (a set of tools), and adds the pricing rule used. That distinguishes it from pricing-lookup siblings like get_pricing and price_changes, though it never names them.

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 phrase "useful for 'what would this stack cost' questions" gives a real usage cue and implicitly frames it as an aggregation tool rather than a per-tool price lookup. However, no alternative is named and there is no when-not guidance, so the agent must infer the boundary with get_pricing.

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