Set DNS session city

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

Beyond the sparse openWorldHint annotation, the description discloses the session/cookie side effect, the global impact on later tools, and an explicit latency range of 15–40 seconds. These behavioral details are meaningful and not derivable from the annotations or schema.

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 short sentences deliver purpose, prerequisite, side effects, and latency with no filler. The main purpose is front-loaded and every sentence earns its place.

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 state-changing tool with one required parameter and clear schema coverage, the description covers the key practical concerns: prerequisite, global effect, and timing. It does not describe what the response contains, but there is no output schema and this is a setter, so the main usage context is adequately 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 input schema already fully describes all three parameters, including the city name origin and optional cityId/citySlug semantics. The description adds a prerequisite link to dns_search_cities, but does not go further in explaining parameter selection or precedence, so it sits at the baseline for high schema coverage.

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: 'Change city for the session'. It clearly separates this setter from sibling search/get tools by defining its stateful scope and by instructing the agent to call dns_search_cities first, which differentiates the operation from city lookup.

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 gives a clear prerequisite ('Call dns_search_cities first') and warns that the change 'affects prices and stock in all subsequent tools', which tells the agent when and why this tool should be invoked. It does not enumerate exclusions or alternatives, but the usage context is clear enough.

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