get_portfolio_performance

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

With no annotations, the description must disclose behavior. It clearly states '[Ads / read]' (read-only) and 'Hosted endpoint only; this local stdio server is an introspection stub,' which is a critical behavioral trait. It does not detail pagination or authentication, but the stub nature is adequately communicated.

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 extremely concise: two sentences that front-load the purpose and then clarify the hosting context. Every sentence adds value without redundancy.

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 the tool has 7 optional parameters and no output schema, the description provides high-level purpose and stub status but omits expected return structure. For an agent to fully understand invocation, more detail on output format would be beneficial, but the description is adequate for an introspection stub.

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. The description adds no further meaning to parameters beyond what the schema already provides. It does not elaborate on how parameters like 'filters' or 'limit' affect results.

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 it's a read operation for Sponsored Products portfolio-level performance rollups, distinguishing it from other performance tools (e.g., get_campaign_performance, get_adgroup_performance). The '[Ads / read]' tag and mention of 'Sponsored Products' provide specific verb-resource-scope clarity.

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 for portfolio-level Sponsored Products performance but does not explicitly state when to use this tool versus alternatives. It mentions 'Hosted endpoint only' which hints at environment restrictions but lacks direct guidance on tool selection among many sibling performance tools.

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