Agents I Know

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description adds genuine context beyond that — it preselects the first available contact rather than opening an empty view — but says nothing about what happens when no contacts exist or what the call actually returns to the agent.

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?

A single short sentence with zero filler, front-loaded on the verb and resource. Every clause earns its place by adding the preselection behavior.

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?

An output schema exists, so return values need not be explained, and a zero-param read-only navigation tool has a low bar. What remains thin is the edge-case behavior (empty contact list) and the relationship to the sibling contacts tools.

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 tool takes zero parameters, so the baseline is 4; there is nothing for the description to disambiguate. The mention of "first available contact" implicitly clarifies that selection is automatic rather than caller-specified, which is a small plus.

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 (Open) and a named resource/view ("Agents I Know"), plus the side effect of preselecting the first available contact. It is distinguishable from the generic open_agent_contacts sibling by the named view, though the description never says how the two differ.

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?

Usage is only implied: opening a named contact view suggests navigating to the contacts UI, but there is no explicit when-to-use, no when-not-to-use, and no reference to the obvious alternatives (open_agent_contacts, search_agent_contacts, open_file_manager) even though they appear as siblings.

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