system_identity

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

No annotations are provided, so the description carries some burden. It discloses the tool is a read-only introspection operation by saying 'Return', which is helpful. However, it doesn't disclose what specific fields are included (OS name, version, architecture, runtime version, etc.) or whether any side effects may occur—though for an identity tool, side effects are unlikely and the lack of parameters supports a read-only assumption.

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 short sentence that is front-loaded with the verb and resource. It is appropriately concise for a zero-parameter introspection tool. It could perhaps enumerate the identity details it returns, but it does not waste words.

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 zero-parameter read-only identity tool, the description is mostly complete. However, there is no output schema, so the agent does not know what specific identity fields will be returned (e.g., OS type, kernel version, runtime name, runtime version). This is a modest gap given the tool's simplicity.

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 zero parameters, so the schema is trivially complete. The description adds no parameter details because none exist. This is a no-argument tool, so parameter semantics are inherently clear.

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 clearly states the tool returns operating-system and runtime identity. It uses a specific verb (Return) and a distinct resource. However, it doesn't explicitly distinguish itself from siblings like process_summary or network_summary, though the 'system_identity' name makes the distinction reasonably clear.

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: call this when you need OS and runtime identity. It provides no explicit guidance on when not to use it or alternatives like system_resources, process_summary, or network_summary. The implied context is adequate but not explicit.

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