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

Beyond the annotations, the description discloses real behavioral context: the exact fields returned and the protection rule (EMCP Tools/Elementor plugins can never be disabled via MCP), which explains why a caller may see odd entries. The closing sentence about the server marking it read-only largely restates readOnlyHint, so it adds little, but the protection semantics are genuine added value.

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 returned-field list is front-loaded and the status filter is mentioned early, with no padding in the middle. The final "Through Royally: its server marks it read-only, so it runs straight away" sentence is vendor jargon that duplicates the annotations and could be cut.

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, the description usefully compensates by naming the fields each plugin record carries, and both parameters (one implicitly) are covered by the schema. For a small, non-paginated read-only listing this is essentially complete, missing only sibling differentiation.

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% with both parameters documented as enums, so the schema does the heavy lifting and a 3 baseline applies. The description mentions the optional status filter but adds no semantics beyond the enum, and it never mentions the site_id parameter at all.

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 names a specific verb and resource ("Lists installed WordPress plugins") and enumerates exactly what each entry contains (status, version, update availability, protection flag). It is clear on its own, but it never mentions the obvious sibling alternatives (emcp-tools-search-plugins, emcp-tools-list-plugin-updates, wp_list_plugins), so an agent cannot tell from the text alone when it differs from those.

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: it says there is an "Optional 'status' filter" and that some plugins are protected, which hints that a full inventory is the default. There is no explicit "use this when X; use search-plugins instead when Y" routing despite several near-duplicate plugin-listing siblings.

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