pnl_by_asinPer-ASIN P&L rows for a date window (optionally one ASIN): sales, units, fees, COGS, margins, TACoS, stock.
| Name | Required | Description | Default |
|---|---|---|---|
| asin | No | ||
| date_to | No | ISO date; default today | |
| currency | No | ||
| group_by | No | ||
| date_from | No | ISO date; default 30d ago | |
| seller_connection_id | No | Which seller connection (see account_sellers). Optional when the token has exactly one. |
Changes observed during successful MCP inspections. Dates show when Glama detected each change.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already declare readOnlyHint=true and destructiveHint=false, so the tool is known to be safe. The description adds useful context about what the rows contain (sales, units, fees, COGS, margins, TACoS, stock) and the date-window scoping, but does not disclose aggregation behavior, currency handling, or output details.
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 compact sentence that front-loads the core resource and lists the important metrics. There is no filler or redundancy, and each phrase adds value.
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 six-parameter tool with no output schema and many sibling P&L tools, the description is adequate but not fully complete. It names returned metrics and the main optional filter, but omits group_by aggregation behavior, currency details, and guidance on when to prefer this over other pnl_* tools.
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 only 50%, so the description needs to compensate. It clarifies the date window and optional single-ASIN filtering, but does not explain group_by or currency semantics. This is partial compensation, not complete.
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 states a specific resource ('Per-ASIN P&L rows') and the key metrics included, making it clear this is a product-level profitability read. It does not explicitly differentiate itself from sibling tools like pnl_summary or pnl_breakdown, but the 'Per-ASIN' focus and title 'P&L: By product' give adequate direction.
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 when per-ASIN P&L data for a date window is needed, and optionally for a single ASIN. It does not explicitly state when not to use it or name alternatives among the many pnl_* siblings, so the guidance is implied rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.