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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering safety. The description adds valuable context beyond this by specifying exactly which metrics are included in the summary (total conversations, unread count, sentiment breakdown, response time metrics). This clarifies the tool's behavioral output without contradicting the annotations.

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 a single sentence of about 17 words, front-loaded with the core action 'Get a summary of the unified inbox'. It efficiently communicates the purpose and output components without any wasted 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?

For a simple tool with one optional parameter and no output schema, the description lists the key components of the summary but omits important context such as the default value for timeRange when the parameter is not provided. Since the schema does not specify a default, this ambiguity leaves the description slightly incomplete for an agent deciding whether to pass the parameter.

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 has 1 parameter with 100% description coverage, and the schema already describes 'timeRange' as a time range for summary metrics with enum values (24h, 7d, 30d). The description adds no additional meaning about this parameter, so the baseline 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's purpose: 'Get a summary of the unified inbox' with specific metrics listed (total conversations, unread count, sentiment breakdown, response time metrics). It uses a specific verb and resource, making it distinct from sibling tools like list_inbox or get_conversation, though it does not explicitly mention alternatives.

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 implies usage context: when you need a high-level summary of inbox metrics. However, it does not explicitly state when to use this tool over alternatives, nor does it provide any exclusions or prerequisites. The usage guidance is only implicit.

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