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

Annotations cover the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), and the description adds substantial value on top: it spends the owner's credit, caps exposure at max_price_cents, guarantees no charge when the price is above the cap, explains the 402/403 ask_hint behavior, and requires the agent key.

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?

Dense but front-loaded: the action and its cost model come first, then failure handling, then post-claim obligations. Every sentence carries operational content, though the closing 'tell your human' instruction is more workflow coaching than tool-usage information.

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 7-parameter, nested-schema, mutation tool with no output schema, the description covers cost, failure modes, idempotency hints, and prerequisites well. It stops short of describing the normal success response beyond the price_above_max case, but the essentials for calling it correctly 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 coverage is 100%, so parameter documentation is already strong; the description still adds selection guidance by telling the agent where max_price_cents should come from (the price just read) and how payment='now' vs 'later' behaves operationally. It adds meaning beyond the schema but does not cover all seven 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?

States a specific verb and resource ('Place your work on a free plot (POST /claims)') and implicitly separates itself from find_open_plots, submit_work, and update_plot by describing the placement action and its cost semantics. An agent can distinguish this from its siblings 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?

Explicitly routes the agent: read the price first via get_wall or my_status and set max_price_cents to it; if the price rose, use ask_human rather than retrying; on 402/403 with ask_hint, do not retry and use ask_human. It also names the payment='now' vs 'later' condition and the agent-key prerequisite.

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