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

Annotations declare destructiveHint=true and readOnlyHint=false; the description earns credit by specifying exactly what is destroyed ('test_steps, when given, REPLACE the case's steps') and by disclosing the merge invariant for all other fields. This is precisely the additive context the destructive hint cannot convey.

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?

Three tight sentences with zero filler; the merge rule, the replace/append distinction, and the deletion exclusion are all front-loaded before any field-specific detail.

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 14-parameter mutation tool with no output schema, it covers the highest-risk behaviors (partial update, step replacement, no delete). It omits permission/auth requirements and whether module_ids appends interact with test_steps replacement, which would be the next most useful detail.

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%, so baseline is 3. The description goes slightly beyond by stating a tool-wide merge rule that governs every optional parameter, and by contrasting replace (test_steps) with append (module_ids) semantics that would otherwise have to be inferred field-by-field.

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 ('Edit an existing test case') and immediately qualifies the semantics with 'fields are merged — only what you pass changes'. It implicitly contrasts with tm_create_test_case/tm_update_test_run by saying 'existing', though it never names a sibling explicitly.

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 operational guidance: partial updates are safe (merge), test_steps replaces rather than appends, module_ids appends, and deletion is explicitly unavailable 'through this connection'. It rules out the delete use case but does not name the alternative tool or surface for deletion.

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