build_proxy_connection_string

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

Annotations only declare readOnlyHint=true, so the description must carry the behavioral burden, and it does: it discloses that the tool 'Fetches the account's own credentials' so the output 'CONTAINS THE PROXY PASSWORD', that it validates targeting and explains unsupported combinations rather than returning a broken string, and it establishes a secret-handling protocol (use the credential for the task, don't repeat it, show only on explicit request). This goes well beyond what annotations provide.

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?

The description is front-loaded with purpose, followed by usage triggers, then behavioral and secret-handling notes. At roughly 150 words it is on the longer side, but the SECRET HANDLING paragraph earns its length given the credential-exposure risk, and there is no filler or repetition of schema content.

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 28-parameter tool with no output schema, the description covers the critical gaps: what the output contains (connection strings plus a verification curl command), what happens on invalid combinations, and the live-secret hazard. The detailed schema descriptions compensate for most remaining gaps, though the exact return object shape (e.g., reported session ids) is only hinted at via the session_id parameter description.

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 baseline is 3 and the description isn't required to document parameters. It adds a modest conceptual framing — 'geo targeting, sticky sessions and expert filters encoded into the password' — which explains how the many parameters materialize in the output, but it provides no per-parameter detail beyond the already-thorough schema.

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 and resource: 'Build ready-to-use Evomi proxy connection strings' with a clear deliverable ('plus a curl command to verify them'). It distinguishes itself from siblings by stating exactly which user requests route here ('a US residential proxy', 'proxies for Berlin', 'a sticky session'), separating it from generate_proxy_list and get_proxy_credentials without ambiguity.

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 clear, concrete usage context with quoted example user requests ('how to configure a proxy in code') that an agent can match against. However, it names no explicit exclusions or sibling alternatives — generate_proxy_list is a plausible alternative for bulk proxy generation, and the description never explains when to pick that instead.

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