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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: it sends nothing about the user (privacy) and that it takes no input, which reassures an agent worried about side effects. No rate limits or failure modes are mentioned, but none are plausible for a static checklist.

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 with the imperative "Call this first" front-loaded, followed by what it returns and the privacy guarantee. Every sentence carries distinct information and nothing is padded.

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?

An output schema exists, so the description needn't detail return values, yet it still summarizes the three payload components (per-system counts, privacy rule, missing-number handling). For a zero-parameter read-only lookup this is fully sufficient to call correctly.

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?

Zero-parameter tool, so the baseline is 4. The description confirms "takes no input," which is redundant with the empty schema but harmless and consistent with additionalProperties=false.

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 and resource ("returns what to count in each kind of system") and enumerates the system categories covered (chat, CRM, support, docs, code, email, project, finance), plus the privacy rule and missing-number handling. Combined with the title and "call this first," an agent can tell this is a prerequisite checklist distinct from estimate_data_value and request_offer without opening any 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?

"Call this first" gives an explicit ordering constraint that routes the agent ahead of the estimating siblings. However, it never names those siblings as alternatives, nor does it state when this tool can be skipped (e.g., if the agent already knows what to count), so there are no exclusions.

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