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

Annotations already declare readOnlyHint=true, and the description adds real context beyond that: the data source (live_specs_ext control-plane view), the underlying PostgREST call with limit=1, and the fact that both the serialized spec and its compiled form come back. It does not say what happens on a non-matching name or whether 'live' excludes unpublished drafts, but it materially enriches the safety-plus-behavior picture.

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?

Two compact sentences with the resource and return payload front-loaded, followed by a short provenance line. The PostgREST endpoint string is arguably implementation detail, but it is brief and plausibly useful for debugging; nothing is padded.

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?

There is no output schema, so the description correctly compensates by naming the returned fields (spec, built_spec), and the single input is fully documented. The residual gap is failure behavior for an unknown catalog_name and explicit live-vs-draft scope, which keeps it short of a 5.

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% and the single parameter already carries its own description with an example, so the schema does the heavy lifting. The description's restatement of 'exact catalog_name' reinforces strict-match semantics but adds no format, casing, or escaping detail beyond what the schema supplies — baseline 3.

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 verb and resource ('Get one live catalog entity') and enumerates what is returned ('full serialized spec and compiled built_spec'). The word 'one' plus 'exact catalog_name' cleanly separates it from estuary_list_catalog and estuary_list_draft_specs, which are the obvious lookalikes among the siblings.

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 exact-name requirement implies this is a point lookup rather than a search, and 'live' hints it is not for drafts. But it never names an alternative (e.g. estuary_list_catalog for discovery or estuary_list_draft_specs for drafts) or says what to do when the exact name is unknown, so the guidance remains implied rather than explicit.

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