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

Annotations already declare idempotentHint=true and readOnlyHint=false, so the 'idempotent upsert' phrase is largely redundant. The description earns credit for genuinely extra context: 'Owner-gated' (auth requirement) and the non-obvious note that the Base payout address is 'stored only' and '▲ are non-redeemable, so there is no cash-out' – behavior an agent could not infer from the schema or 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 action and scope, with the alternative path and constraints appended. Every clause carries information, though the parenthetical field list and the '▲' shorthand are slightly compressed and mildly cryptic.

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 9-parameter mutation with annotations and no output schema, the description covers what the tool does, the auth gate, idempotency, the payout caveat, and the preferred alternative. It omits return/response behavior and how the required 'handle'/'secret' interact with registration, but the essentials for correct invocation are present.

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 description coverage is 100%, so the schema already documents all 9 parameters with examples, making 3 the baseline. The description names the same fields (display_name, skills, city/country, rate expectations, payout address) without adding syntax or constraints beyond what the schema states; its only extra semantic (no cash-out on payout_address) is behavioral rather than parametric.

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 with scope: 'List yourself (or your operator) as a hireable HUMAN worker in the directory', then enumerates the profile fields involved. It is clearly distinguishable from siblings like human_task_post, human_task_list, and human_browse, which deal with tasks rather than a worker profile.

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?

Gives a real routing signal: 'Humans usually join via the web form at /humans/join instead', which tells the agent when this tool is not the preferred path. It also flags 'Owner-gated' as a precondition. It stops short of explicitly contrasting with the closest siblings (e.g. human_task_post), so not a full 5.

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