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

With no annotations, the description carries the full behavioral burden. It discloses the core behavior and the fact that a result is returned, which is adequate for a pure arithmetic function. However, it says nothing about edge cases, error handling, or whether the operation is stateless — though the simplicity lessens the severity of these omissions.

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?

One sentence, ten words, zero fluff. The action verb and resource are front-loaded and every word earns its place. There is nothing extraneous.

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?

The tool is trivial in complexity, so the schema's thorough parameter docs and the description's clear operation statement are largely sufficient. Could theoretically note edge cases or the return type explicitly, but the implied number return is practically unambiguous.

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 input schema already provides 100% coverage, so the baseline of 3 applies. The description adds no extra meaning about the parameters beyond what the schema states — it simply confirms the operation performed on them.

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?

Names a specific verb ('adds') and resource ('two numbers') and goes beyond a mere label by stating the outcome ('returns the result'). The sibling tool get_system_status is so categorically different that there is no realistic ambiguity about which tool this is.

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 intended use is obvious for the operation being performed, but no guidance is given for distinguishing when to use this over an alternative. There is no when-to-use or when-not-to-use context — the usage is implied but never stated.

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

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

There are no annotations, so the description carries the full burden. It clearly indicates a read-only fetch behavior, which is useful, but it does not disclose whether the returned status is a plain object, whether errors or empty values are possible, or any environment-specific caveats. Given the simple nature of a status query, this is adequate but not thorough.

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, front-loaded sentence that immediately states the action and lists the relevant content. There is no filler or repetition of the tool name.

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?

With no output schema or annotations, the description provides enough grounding about the expected contents, including four concrete status fields. It stops short of describing the exact return shape or exception behavior, but for a zero-parameter status query this is a reasonable, workable definition.

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?

There are 0 parameters, so there is no parameter semantics to explain. The description compensates by enumerating the kind of data that will be returned, which helps clarify what 'status' means even without an output schema.

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 uses a specific verb ('Retrieves') and names the resource ('system runtime status') along with concrete fields: Node version, OS, uptime, and timestamp. This clearly distinguishes it from sibling add_numbers, though it does not explicitly name the sibling as an alternative.

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?

No guidance is given for when to use this tool versus alternatives or when not to use it. While the sibling 'add_numbers' is clearly unrelated, there is no explicit usage context or exclusion criteria.

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