invariance_agent_get

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description's safety profile is covered. The description adds a useful behavioral detail: 'Requires a user-session JWT bearer', which informs authentication prerequisites beyond what annotations provide. No contradictions with annotations.

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, tightly worded sentence that front-loads the action and resource, then adds a crucial auth note. No redundancy; every word contributes value.

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?

This is a simple single-parameter, read-only tool with no output schema. The description covers the operation and auth requirement. While it does not explicitly state the return value shape, for a straightforward 'get by ID' operation, the given context plus annotations is sufficient for an agent to call it 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?

Schema description coverage is 100%, and the schema already states 'Agent ID' for the id parameter. The description's phrase 'by ID' aligns with the schema but does not add any additional meaning (e.g., type, format, constraints) beyond what is already documented. Baseline of 3 is appropriate for high schema coverage.

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 ('Fetch') and a specific resource ('a single agent by ID'), which clearly distinguishes this from sibling tools like invariance_agent_list (which lists agents) and invariance_agent_me (which fetches the current user's agent). The scope is unambiguous.

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 the tool is for fetching a single agent by ID, but it does not explicitly state when to choose this over alternatives (e.g., 'Use agent_list to get all agents, use agent_me for the current user'). No exclusions or alternative routing is provided, so the guidance is implied rather than explicit.

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