Sign in to Yandex

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

Beyond the annotations (readOnlyHint=false, openWorldHint=true), the description adds critical behavioral details: it opens a browser, code returns automatically via local redirect, fallback returns a URL, token lasts ~1 year, and it should be run once. These details are not in the annotations and give the agent a clear model of the tool's side effects.

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 three sentences, each carrying essential information: what it does, how the flow works, when to run it. It is front-loaded with the purpose and avoids any redundancy or fluff.

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?

The description fully covers the tool's operation given its simplicity: it explains the typical flow, the fallback path, the token validity, and the usage context relative to sibling data tools. No output schema exists, so describing the return value is not strictly necessary, and the description is sufficiently complete.

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 schema description for the single parameter 'oob' is already clear ('Force the copy-paste flow...'), and the tool description elaborates on the default automatic flow and the fallback to submit_code. This adds context on when one might set oob, but it doesn't explicitly tie the parameter to the fallback scenario, so a small gap remains.

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 'Sign in to Yandex from here,' clearly stating the verb (sign in) and resource (Yandex). It distinguishes itself from sibling data tools by focusing on authentication, and the description of the browser-approval flow reinforces its unique purpose.

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?

The description explicitly states when to use the tool: 'needed before the data tools if you are not signed in yet.' It also provides an alternative flow by naming 'submit_code' when the local port is unavailable, giving clear context on when to use this tool versus fallback.

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