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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely non-obvious interpretive context: total_revenue_usdc covers only swarm listings while storefront.revenue_usdc is the full settled ledger — a distinction an agent could easily misread. It does not discuss auth or quota behavior tied to agent_id.

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 compact sentences, front-loaded with the return contents before the field caveat and the sequencing hint. No filler or restatement of the tool title.

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 return values need not be enumerated in prose, and the description correctly avoids that. Coverage is strong for a read-only report; the only minor gap is that it doesn't explain what the optional agent_id changes about the result set beyond quota accounting.

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% and the single parameter agent_id is fully described in the schema ('Optional agent identity for quota accounting'). The description adds no parameter-level detail, so this is the baseline case where the schema does the work.

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+resource ('Get swarm composite economics') and enumerates the exact outputs: spend, composite sales, LTV:CAC, margins, per-source scores. It further disambiguates two same-named revenue fields, so an agent can distinguish this report from sibling economics tools 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?

Explicitly gives sequencing guidance: 'Call after swarm.research or swarm.settle to inspect realized economics,' which tells the agent when this tool is appropriate relative to two named siblings. It stops short of stating when not to use it or naming an alternative reporting tool.

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