Draw user growth over time

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

Beyond the readOnlyHint annotation, the description discloses that the tool returns a rendered chart in MCP-Apps-capable hosts and a text summary elsewhere, plus the period totals. It also reveals rejection behavior for unverified hosts, adding critical context annotations alone do not 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 two sentences: the first precisely states function and output, the second gives usage guidance and a condition. Every sentence adds value, and the key action is front-loaded. No superfluous words.

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?

Given three parameters, no output schema, and no nested objects, the description fully covers the tool's behavior: it explains the return format (chart/text + totals), the environmental dependency (MCP-Apps-capable), and the host verification requirement. This is sufficient for the agent to handle diverse contexts.

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 baseline is 3. The description adds no new parameter information beyond what the schema already provides (e.g., days default, host verification). However, it does not contradict or omit schema details, so a score of 3 is appropriate.

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 clearly states the tool renders an interactive line chart of unique visitors and page views over time for a verified host, and returns period totals as text. This specific verb-resource pairing distinguishes it from sibling tools like get_host_analytics or get_host_top_pages, which provide raw data without visualization.

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 tells when to use: 'Use when asked to chart, graph, draw, or visualize growth or traffic for a subdomain.' It also sets a precondition: 'The host must be a verified origin of the project, or the request is rejected,' guiding the agent on necessary validation before invocation.

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