agent_index

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

With no annotations, the description carries the full burden, and it mostly succeeds: 'Open' signals a non-mutating operation, and the description discloses what the agent receives (persona, index.md, all concepts) and how it behaves when switching agents. It does not explicitly state 'read-only' or 'no side effects,' though the wording strongly implies both.

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 short sentences: the first defines the function, the second states when to call it, and the third explains how to reuse the tool for switching. There is no filler, no repetition of schema data, and the most important information is front-loaded.

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 simple one-parameter tool with an output schema, the description covers purpose, timing, and parameter behavior well. It would be slightly more complete if it pointed to list_agents for discovering IDs or explicitly excluded write behavior, but neither omission prevents correct use in the described scenario.

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 schema's only parameter, agent_id, has 0% description coverage, so the tool description must add meaning. It does by making clear the parameter selects which agent's wiki to open and by explaining that passing a different agent_id switches agents. It does not document format or how to discover valid IDs, but for a single obvous string parameter this is sufficient.

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 action ('Open an agent's wiki') and names the returned contents: persona preview, index.md text, and all concepts. This is clearly distinct from a single-page wiki_read or search tool in substance, but it does not explicitly contrast with sibling tools or name alternatives.

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?

It gives an explicit trigger: 'Call this when waking an agent in a new project, before working.' It also adds a practical switching pattern: 'Switch agents by calling this with a different agent_id.' It lacks explicit when-not-to-use guidance or named alternatives, but the primary usage context is unmistakable.

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