get_price_history

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

With no annotations, the description carries the full burden and does disclose the key behavioral trait: data comes from persisted weekly snapshots, which sets the granularity expectations for any date query. It also describes return contents (timeseries, total change %, earliest/latest points) despite there being no output schema, though it says nothing about behavior for untracked SKUs or empty history.

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 core capability is front-loaded in sentence one and the rest is supporting evidence. Some phrasing is promotional ('neither AWS Calculator nor GCP Estimator preserves historical pricing', 'citing audit-traceable historical numbers to a CFO') and could be trimmed without losing actionable information.

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 three-parameter read tool with no output schema, the description covers purpose, data source, granularity, and return shape well enough to call correctly. The remaining gap is edge-case behavior — what happens for SKUs never tracked (where list_tracked_skus would apply) or a 'since' date preceding available history.

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 67% and the schema already documents sku examples and the 'since' semantics. The description adds only the pairing requirement ('specific (cloud, sku)') and indirectly hints that 'since' aligns to weekly snapshots; it does not clarify date boundaries, null handling, or the cloud enum values beyond what the schema provides.

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 first sentence gives a specific verb and resource ('Return the multi-cloud price history for a specific (cloud, sku)') and the second states the distinctive mechanism (dated snapshots from weekly auto-refresh). This clearly separates it from the current-price siblings like get_aws_price and get_azure_price without the agent needing to open a schema.

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?

It supplies concrete use cases (validating commitment timing, spotting quiet increases, audit-traceable numbers) and explicitly contrasts with external tools that lack history. It stops short of naming the sibling tools that should be used instead for point-in-time pricing, so the when-not guidance is implied rather than stated.

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