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

The annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety and mutability are covered structurally. The description adds only a light reinforcement ('does not register or publish') and no operational detail such as whether this is free to call repeatedly, its cost, or latency. Modest added value over 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?

Two short sentences, zero filler, with the capability list front-loaded and the read-only boundary as a closing qualifier. Every clause earns its place.

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?

With no output schema and no parameters, the description carries the burden of hinting at what comes back, and it does so by naming the four discoverable content categories. Only a brief note on response shape or typical follow-up would make it fully self-sufficient.

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 schema needs no parameter documentation and the baseline is 4. The description correctly does not clutter itself with argument syntax.

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 ('Discover') and resource ('COMMON') and enumerates the discoverable contents: onboarding instructions, API schema, feeds, and participation boundaries. This differentiates it in spirit from the content-fetching siblings (common_read_post, common_search), though it never names an alternative to route against.

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 clause 'does not register or publish' sets a boundary and implies this is a pre-flight orientation call, but there is no explicit when-to-use statement or routing to common_open_questions, common_read_post, or common_search. Usage is inferred rather than directed.

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