substack_user_search

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

With no annotations, the description carries the behavioral burden. It discloses that only public profiles are searched, that results include subscriber signals, and that pagination is 20 per page with variable totals. It does not cover failure modes or exact response structure, but it provides meaningful operational behavior for an agent.

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?

Four front-loaded sentences, each carrying useful information: scope, matching criteria, workflow advantage, and pagination guidance. There is minor redundancy between the first sentence and the start of the second ('Search public... writer profiles' vs 'Searches public... profiles'), but no wasted material.

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?

For a two-parameter public search tool with no output schema, the description covers what is searched, how matching works, pagination expectations, and the subscriber-signal content of results. It relies on the /substack/user comparison for result semantics, which is sufficient given the rich sibling context.

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%, and the schema already documents both parameters, including 'Search text matched against profile names and handles' and 'Zero-based page.' The description mostly restates query semantics and adds pagination/output context rather than new parameter-level meaning, so the baseline 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 opens with a specific verb and resource ('Search public Substack writer profiles') and narrows the search mode ('by name or handle'). This clearly distinguishes the tool from general-purpose substack_search and from per-profile substack_user lookups.

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 gives an explicit workflow directive: 'a search enumerates writers without a second lookup per profile' and advises using 'has_more rather than assuming a fixed depth.' It provides clear context but does not explicitly state when not to use the tool or contrast it with generic substack_search.

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