search_posts

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

Beyond the readOnlyHint annotation, the description discloses pagination behavior ('One page per call, at most 50 results'), continuation via 'next_offset', server-controlled indexing limitations, and metadata-only return values. These details set accurate expectations about how the search behaves and what it cannot guarantee.

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 description is three tight sentences with no filler. The main scoping is front-loaded, followed by pagination caveats and the metadata-only/content-fetching distinction.

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?

Given the presence of an output schema and readOnly annotations, the description covers everything needed to call the tool correctly: scope, statuses, pagination limits, continuation mechanism, and search-quality caveats. The minor offset/next_offset wording ambiguity is resolvable from the input schema.

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?

With 0% schema description coverage, the description compensates by explaining page size, pagination continuation, and the published/draft/scheduled statuses. However, it references 'next_offset' without explicitly mapping it to the schema's 'offset' parameter, and it leaves limit defaults to the schema's own constraints.

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 action ('Search'), a precise resource ('this publication's published, draft, or scheduled archive'), and the mechanism ('Substack's server-side query'). It also explicitly distinguishes itself from content-fetching tools by stating 'Returns metadata only; get_post/get_draft fetch full content.'

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 description routes full-content needs to get_post/get_draft and clarifies that search is not a guaranteed full-text scan. It does not explicitly contrast search_posts with the list_* siblings, so an agent must infer when to choose query-based search over simple enumeration.

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