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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioural context about the response shape: each gap carries the rival pages and the nearest page on the site, one gap is surfaced first, and page titles are wrapped in quotes. It says nothing about ordering beyond 'first', result volume, or how the limit interacts with ranking.

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?

One sentence, front-loaded with the resource label 'Content gaps:', and every clause carries distinct information about scope or return shape. The clause 'the one most rivals cover first' is placed awkwardly enough to require a second read, and the 'quoted' formatting note reads as an aside.

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 carries the burden of describing returns, and it does partially: gap subject, rival pages, nearest page here, and title quoting. It omits how gaps are ordered or scored, what happens when the site is unknown or empty, and whether the limit defaults. Adequate but with clear gaps for a tool whose output is entirely undescribed structurally.

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 coverage is 100%, so both the domain format and 'how many to return' are already documented in the schema. The description contributes no extra parameter meaning, though the 'one most rivals cover first' clause hints that results are ranked rather than arbitrary. Baseline 3 applies.

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 defines a specific resource precisely: subjects rivals write about that nothing on the site covers semantically, plus the one most rivals cover first. This is far more concrete than the title 'Find content gaps'. It does not, however, distinguish this from near-neighbours like mttr_competitors, mttr_similar or mttr_topics, so an agent must infer the boundary.

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?

No when-to-use statement, no prerequisites, and no named alternative. With siblings such as mttr_competitors, mttr_content_next and mttr_topics in the same family, the agent gets no signal about which tool answers which question. Usage is only implicit in the concept definition.

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