Megamarket Self-Check

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

Beyond the readOnly/idempotent annotations, the description discloses that the tool performs a live CDP search, has an external transport dependency, and precisely defines the drift vs inconclusive judgment rules. It even explains environment expectations about Chrome challenge state. This is substantial behavioral context.

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 definition is front-loaded with its core purpose, then uses short structured lines for verdict semantics and return format. Every sentence carries diagnostic value; there is no filler.

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 no-input canary tool with an output schema, the description fully explains the operation, the meaning of each verdict class, the transport-vs-drift distinction, and the expected outcome on machines with an unmet Chrome challenge. An agent has enough context to invoke and interpret the tool correctly.

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 tool takes zero parameters and schema coverage is complete, so there is nothing for the description to add about inputs. The baseline of 4 applies for a no-parameter tool; the description correctly spends no space on parameters.

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 names a specific operation—'Posts one live search through CDP and checks items parse'—and frames it as a 'Structural drift canary for Megamarket (tri-state)' with a distinct verdict semantics. This distinguishes it from megamarket_search/megamarket_card and the other selfcheck tools.

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 its use case via 'drift canary' and clarifies when the verdict should be read as inconclusive, but it never explicitly says when to call this instead of alternatives such as megamarket_search or another selfcheck. There are no when-not-to-use or alternative-routing statements.

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