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

With no annotations, the description carries the full burden and does disclose meaningful traits: an API key is required, compact pages cap at 20 rows with no counts, empty pages terminate results, search ranks all tokens before subsets, misses return nearest ids, and split-mode full details exclude model facts and counts. It omits error/rate-limit behavior, but the coverage is unusually rich for an unannotated tool.

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?

Nine fragmentary sentences are strung together with undefined jargon ('Spec', 'unknown facet', 'split-mode') and no front-loaded statement of what the tool is. The opening sentence is a rhetorical question that delays rather than delivers the purpose, so much of the prose does not earn its place.

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 7-parameter tool with no annotations and no output schema, the description should describe the return shape, but it only says 'Returns ids and task types' and notes counts are omitted. Behavioral details are comparatively complete, yet the actual response structure an agent needs is left unclear.

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%, so the schema already documents all seven parameters; the baseline is 3. The description adds marginal semantic nuance (paging applies to cross-section lookups, search ranking order, split-mode exclusions) but no syntax or format detail beyond what the schema provides.

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 the vague rhetorical 'What can a Spec say?' and only states 'Returns ids and task types', which is narrower than the 14 sections the schema exposes (models, providers, benchmarks, etc.). It implies a vocabulary-lookup resource but never names a clear verb+resource and does not distinguish itself from siblings like model_info or list_use_cases.

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?

It gives concrete routing advice: 'One vocabulary lookup per unknown facet, then decide' and 'Use decide to compare models', naming the alternative sibling for a specific task. It stops short of explicitly stating when not to use it or how it relates to the other seven siblings.

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