Plugins’ data

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

Annotations already cover readOnly, idempotent, non-destructive and closed-world, so the safety profile is handled. The description adds genuinely useful context the annotations cannot: the result set is server-dependent ('what's here depends on the server'), which tells the agent not to cache or assume a fixed list. It doesn't describe pagination or empty-result behavior, but for a zero-arg discovery call that is minor.

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?

Two sentences, no filler, with the actionable directive ('call this first instead of guessing') placed last as a clear closing instruction. The first sentence is dense with parentheticals that could be split, but each clause carries information about what comes back and who consumes it.

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?

There is no output schema, so the description carries the burden of explaining return values, and it does: namespaces, resource paths, and event topic strings with their format and consumers. Combined with the 'depends on the server' caveat and the call-first advice, an agent has everything needed to invoke 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?

The tool takes no parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description instead spends its words on the output shape, which is the right allocation here.

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 states the resource precisely: a catalog of other plugins that expose data via WorldAPI, returning each namespace, its readable resource paths, and its event topics. It implicitly separates this from list_plugins by scoping to plugins that 'share their own data through WorldAPI', though it never names list_plugins outright to make the distinction explicit.

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?

'Call this first instead of guessing' is an explicit call-ordering instruction that routes the agent here before attempting read_extension or get_events. It also tells the agent what to do with the results (use paths with read_extension, topic strings with get_events/wait_for_event). It stops short of stating when not to use it or why list_plugins would be preferred in some cases.

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