Renew proxies

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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the account balance is charged immediately, at a per-proxy rate, and auto-renewal settings are left untouched. It does not cover failure modes (e.g. insufficient balance) or reversibility.

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?

Four tight sentences, front-loaded with the action and its cost consequence, then the estimate escape hatch, then preservation of auto-renewal, then sibling routing. Every sentence carries distinct information with no padding.

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?

No output schema exists, and the description does explain what estimate_only returns (a total) while noting the charge behavior of the normal path. It is nearly complete for a 3-parameter mutation tool; only edge-case outcomes such as charge failures or partial-success handling across multiple proxy_ids are unaddressed.

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 all three parameters are already documented in the schema, including the valid period_days values and the estimate_only meaning. The description reinforces estimate_only and adds the per-proxy pricing nuance but supplies no syntax or format detail beyond the schema, so the baseline 3 is correct.

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 ('Extends ... proxies by a period') and immediately scopes the eligible proxy types (mobile, server, backconnect). It also names which resource type it does NOT cover and routes to the correct sibling, so an agent can distinguish it 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?

Gives explicit when-to-use context: use estimate_only=true to price without charging, and use add_residential_traffic instead for residential proxies. This names both a mode-selection condition and the alternative tool for an out-of-scope case, leaving nothing to inference.

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