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

Annotations already declare readOnly, idempotent, closed-world and non-destructive behavior, so the bar is lower, yet the description still adds real context: the data is checksum-pinned and shipped, returned verbatim with limitations/unavailable/unknown states and nonClaims preserved, plus source provenance and an explicit label. The historical-vs-synthetic distinction and the 'not live evidence' warning are behavioral facts an agent cannot get from annotations or 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 core action ('Returns ONE case by exact id'), followed by source, payload guarantees, and the historical/synthetic caveat in short declarative sentences. The middle clause is dense with parenthetical detail, but each sentence carries distinct information with no filler.

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?

Output schema exists, so return-value structure needn't be restated, yet the description still characterizes the payload (envelope verbatim, provenance, label). Combined with the pinned source path, id semantics, and the 'not live evidence' caveat, nothing an agent needs to call and interpret this single-param read tool is missing.

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 enum already constrains values, so the baseline would be 3. The description goes further by explaining why exactness matters (no fuzzy matching) and by giving the semantic meaning of each id — past public-network observations versus a synthetic fixture — which the enum alone does not convey.

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 ('Returns ONE case by exact id') and enumerates the exact valid ids, including what each one is (historical export vs synthetic fixture). An agent can distinguish this read-one-case tool from discover_network_candidates and list_network_profiles without opening any schema.

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?

Gives clear invocation constraints ('exact id; no paths, no prefixes, no fuzzy matching') and a critical usage caveat that 'No case is live evidence', which shapes when the result is appropriate to rely on. It does not, however, explicitly name an alternative tool or say when to prefer those siblings over this one.

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