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

Annotations already declare destructiveHint=true, openWorldHint=true, and non-idempotent, so the safety profile is covered. The description adds genuinely new behavior: per-call quota cost that varies by operation, and the failure mode (a tool error carrying upAPI's error code rather than a broken session). It does not restate or contradict the mutation/idempotency hints explicitly, which would have made it a 5.

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?

Three tight sentences with no filler, front-loading the action, then the prerequisite, then cost and error behavior in order of decision relevance.

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 generic dispatch tool with a nested free-form `input` object and no output schema, the description covers discovery, cost, and failure semantics well. The remaining gap is what a successful call returns (raw operation payload? envelope?), which matters even without an output schema.

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 schema already explains that `slug` must match what `search_ops` returned and that `input` mirrors the operation's listed parameters. The description repeats that relationship without adding format, validation, or edge-case detail beyond it, so baseline 3 applies.

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?

States a specific verb and resource ("Run one upAPI operation by slug") and distinguishes itself from the sibling `search_ops`, which is the discovery counterpart. An agent can tell what this does without opening the 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?

Gives an explicit prerequisite and sequencing rule: discover slugs and their parameters with `search_ops` first, then call this. The alternative tool and the condition for using it are named directly rather than implied.

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