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

Annotations already cover readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description reinforces this with 'Read-only.' It adds one genuinely non-obvious behavioral fact — 'earnings settle non-custodially to your withdrawal address on release' — which tells the agent the tool never moves money itself and settlement happens asynchronously. No contradiction with annotations.

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 sentences, front-loaded with the core purpose. The return-category list is dense but earns its place by teaching the agent the semantic meaning of the output categories, and the closing read-only/settlement note is valuable safety context. Slightly long, but no sentence is wasted.

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 zero-parameter, read-only overview tool whose annotations already carry the safety profile and whose output schema covers the return structure, the description is complete. The non-custodial settlement semantics it adds are exactly the kind of financial knowledge an agent cannot derive from the schema alone.

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?

The tool has zero parameters, which is the baseline-4 case. The schema description already fully covers the only relevant semantic ('No arguments — the owner is derived from the authenticated principal'), so the tool description correctly needs to add nothing about parameters.

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 opens with a specific verb+resource, 'Check how much I have earned and what is pending,' followed by a precise enumeration of return categories (lifetime USDC as seller, in-flight pending amounts, unclaimed claim-later rewards, payout-address balance, buyer spend summary, first-agent reputation). This fully scopes the tool and distinguishes it from all 15 siblings, none of which are earnings-overview tools.

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?

Usage is implied by the purpose statement and the detailed return list, but the description never explicitly states when to use this tool versus an alternative and names no exclusions. The risk is low because no sibling (data_session_query, get_agent_contract, find_paid_work) is a near-alternative, but explicit routing guidance is absent.

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