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

Annotations already declare readOnly/idempotent/closed-world, so the safety profile is covered; the description adds genuinely new behavioral context: the confidence taxonomy (mechanical vs heuristic vs lexical, with lexical decided from lexicon and corpus counts) and the coverage limits. It also previews the shape of a finding (rule §, paraphrase, text, replacement, offsets), which is somewhat redundant with the existing output schema.

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?

Front-loaded with the hard constraint ('Slovenian only') followed by the rule source and the finding shape; every clause carries information. The dense semicolon-chained enumeration is efficient but costs a little parseability, so not a 5.

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, read-only tool with an output schema and full schema coverage, the description supplies exactly the missing pieces: language precondition, rule authority, confidence semantics, and explicit non-coverage. An agent can decide whether to call it and interpret results without further documentation.

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%: `text` (Slovenian, ≤20,000 chars) and `rules` (ids, default = rules measured reliable, see explain_rule) are both documented in the schema. The description adds no syntax or format detail beyond that, so the 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?

States a specific resource (orthography findings) with an explicit authority (Slovenski pravopis 2001) and enumerates the phenomena covered — commas, ne + verb, s/z and k/h, capitals, spacing, dashes, dates, abbreviations. The 'Not checked' list (embedded-clause commas, grammar, loanword spelling) further sharpens the boundary, though no sibling tool (check_text, check_pairing) is named directly.

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?

'Slovenian only' sets a hard precondition and the closing 'Not checked' sentence tells the agent when this tool will not answer. The `rules` parameter description routes to explain_rule for rule ids, giving one concrete alternative path. It never explicitly says which sibling to use instead for grammar or embedded-clause commas, so it stops short of full routing.

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